I have managed to solve my requirement with your generous help. I'm not very satisfied with the overall hackishness, but it solves my requirements. Hopefully it might be helpful to someone else.
Document:
\documentclass[12pt,a4paper]{class}
\usepackage{lipsum}
\projecttitle{My project name}
\metadata{Metadata}
\metadataTwo{Metadata Two}
\metadataThree{Metadata Three}
\metadataFour{Metadata Four}
\metadataFive{Metadata Five}
\metadataSix{Metadata Six}
\begin{document}
\section{Lipsum}
\lipsum[1]
\section{Phasellus eu tellus}
\lipsum[1-12]
\end{document}
Document class:
\ProvidesClass{class}
\LoadClass[12pt,a4paper]{article}
\newcommand{\projecttitle}[1]{\gdef\@projecttitle{#1}}
\newcommand{\metadata}[1]{\gdef\@metadata{#1}}
\newcommand{\metadataTwo}[1]{\gdef\@metadataTwo{#1}}
\newcommand{\metadataThree}[1]{\gdef\@metadataThree{#1}}
\newcommand{\metadataFour}[1]{\gdef\@metadataFour{#1}}
\newcommand{\metadataFive}[1]{\gdef\@metadataFive{#1}}
\newcommand{\metadataSix}[1]{\gdef\@metadataSix{#1}}
\usepackage{polyglossia}
\setmainlanguage{croatian}
\usepackage{fontspec}
\defaultfontfeatures{Mapping=tex-text}
\usepackage{xunicode}
\usepackage{xltxtra}
\setmainfont{Minion Pro}
\usepackage{geometry}
\geometry{%
a4paper,%
hmargin={3.5cm,2.5cm},%
headheight=2cm,%
headsep=1cm,%
marginparwidth=1.1cm,%
marginparsep=0.2cm%
}
\usepackage{fancyhdr}
\pagestyle{fancy}
\usepackage{lipsum}
\usepackage{graphicx}
\usepackage{microtype}
\usepackage{tikz}
\usetikzlibrary{calc}
\tikzstyle{content box}=[]
\usepackage{lastpage}
\def\logowidthratio{0.25}
\def\titlewidthratio{0.5}
\def\rightcolumnwidthratio{0.25}
\newlength\framewidth
\setlength{\framewidth}{\paperwidth-3cm}
\newlength\frameheight
\setlength{\frameheight}{\paperheight-2cm}
\newlength{\logowidth}
\setlength{\logowidth}{\logowidthratio\framewidth}
\newlength{\titlewidth}
\setlength{\titlewidth}{\titlewidthratio\framewidth}
\newlength{\logoandtitlewidth}
\setlength{\logoandtitlewidth}{\logowidth+\titlewidth}
\newlength{\rightcolumnswidth}
\setlength{\rightcolumnswidth}{\framewidth - \logoandtitlewidth}
\newlength{\padding}
\setlength{\padding}{6pt}
\lhead{}
\chead{}
\rhead{}
\lfoot{}
\cfoot{}
\rfoot{}
\renewcommand{\headrulewidth}{0.0pt}
\renewcommand{\footrulewidth}{0.0pt}
\AtBeginDocument{
\newsavebox{\logobox}
\sbox{\logobox}{
\parbox{\logowidthratio\framewidth-2\padding}{
\centering
\rule{\logowidth-2\padding}{2cm}% graphic dummy
}
}
\newsavebox{\titlebox}
\sbox{\titlebox}{\parbox{\titlewidthratio\framewidth-2\padding}{
\centering\large\textsc{Project name}\linebreak\textbf{\@projecttitle}}
}
\newsavebox{\metadatabox}
\sbox{\metadatabox}{
\parbox{\rightcolumnswidth-2\padding}{Metadata: \@metadata}
}
\newsavebox{\docnumbox}
\sbox{\docnumbox}{
\parbox{\rightcolumnswidth-2\padding}{Metadata: \@metadataTwo}
}
\newsavebox{\revisionbox}
\sbox{\revisionbox}{
\parbox{\rightcolumnswidth-2\padding}{Metadata: \@metadataThree}
}
\newsavebox{\contractnumbox}
\sbox{\contractnumbox}{
\parbox{\logowidth-2\padding}{Metadata: \@metadataFour}
}
\newsavebox{\projectnumbox}
\sbox{\projectnumbox}{
\parbox{0.5\titlewidth-2\padding}{Metadata: \@metadataFive}
}
\newsavebox{\bookbox}
\sbox{\bookbox}{
\parbox{0.5\titlewidth-2\padding}{Metadata: \@metadataSix}
}
\newsavebox{\pagenumbox}
\sbox{\pagenumbox}{
\parbox{\rightcolumnswidth-2\padding}{\hphantom{Page: 123 of 123}}
}
\newlength\logoheight
\settototalheight\logoheight{\usebox{\logobox}}
\addtolength{\logoheight}{2\padding}
\newlength\titleheight
\settototalheight\titleheight{\usebox{\titlebox}}
\addtolength{\titleheight}{2\padding}
\newlength\metadataheight
\settototalheight\metadataheight{\usebox{\metadatabox}}
\newlength\docnumheight
\settototalheight\docnumheight{\usebox{\docnumbox}}
\newlength\revisionheight
\settototalheight\revisionheight{\usebox{\revisionbox}}
\newlength\contractnumheight
\settototalheight\contractnumheight{\usebox{\contractnumbox}}
\newlength\projectnumheight
\settototalheight\projectnumheight{\usebox{\projectnumbox}}
\newlength\bookheight
\settototalheight\bookheight{\usebox{\bookbox}}
\newlength\pagenumheight
\settototalheight\pagenumheight{\usebox{\pagenumbox}}
\newlength\rightcolumnheight
\pgfmathsetlength{\rightcolumnheight}{3*(max(\metadataheight,\docnumheight,\revisionheight)+2\padding}
%45 points is sligtly more than 1,5 cm
\newlength\headerfirstrowheight
\pgfmathsetlength{\headerfirstrowheight}{max(\logoheight,\titleheight,\rightcolumnheight,45)}
\newlength\headerheight
\pgfmathsetlength{\headerheight}{\headerfirstrowheight + max(\contractnumheight,\projectnumheight,\bookheight,\pagenumheight)+12pt}
\newgeometry{vmargin={\headerheight+1.5cm,1.5cm}}
\chead{%
\begin{tikzpicture}[remember picture, overlay, semithick, black, inner sep=0, outer sep=0]%
%
% OUTER FRAME AND COPYRIGHT DIVIDER
%
%
%Outer frame
\node (frame) at ($(current page.center)+(0.5cm,0)$) [minimum width=\paperwidth-3cm,minimum height=\paperheight-2cm, draw] {};%
%
%Copyright divider
\draw ($(current page.west)+(0.2cm,0)$) -- ($(current page.west)+(1.8cm,0)$);%
%
%
% CONTENT BOXES
%
%
%Revision information
\node (revision information) at ($(frame.north west)!0.98!(frame.south west)$) [content box, xshift=-0.4cm, anchor=west, rotate=90] {\tiny Revision information text};%
%
%Copyright notice Croatian
\node (copyright hrvatski) at ($(frame.north west)!0.75!(frame.south west)$) [content box, xshift=-1cm, rotate=90] {\parbox{0.25\frameheight}{\tiny\centering \lipsum[13]}};%
%
%Copyright notice English
\node (copyright english) at ($(frame.north west)!0.25!(frame.south west)$) [content box, xshift=-1cm, rotate=90] {\parbox{0.25\frameheight}{\tiny\centering \lipsum[13]}};%
%
%Logo
\node (logo) at (frame.north west) [content box,anchor=north west,outer sep=\padding] {\usebox{\logobox}};%
%
%Title
\node (title) at ($(frame.north west)!\logowidthratio!(frame.north east)$) [content box,anchor=north west, outer sep=\padding] {\usebox{\titlebox}};%
%
%metadata metadata
\node (metadata) at ($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$) [content box,anchor=north west,outer sep=6pt] {\usebox{\metadatabox}};%
%
%Document number metadata
\node (document number) at ($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$) [content box,anchor=north west, yshift=-0.33\headerfirstrowheight,outer sep=6pt] {\usebox{\docnumbox}};%
%
%Revision metadata
\node (revision) at ($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$) [content box,anchor=north west, yshift=-0.66\headerfirstrowheight,outer sep=6pt] {\usebox{\revisionbox}};%
%
%Contract number metadata
\node (contract number) at ($(frame.north west)-(0,\headerfirstrowheight)$) [content box,anchor=north west,outer sep=6pt] {\usebox{\contractnumbox}};%
%
%Project number metadata
\node (project number) at ($(frame.north west)-(0,\headerfirstrowheight)$) [content box,anchor=north west,xshift=\logowidth,outer sep=6pt] {\usebox{\projectnumbox}};%
%
%Book number
\node (book number) at ($(frame.north west)-(0,\headerfirstrowheight)$) [content box,anchor=north west,xshift=\logowidth+0.5\titlewidth,outer sep=6pt] {\usebox{\bookbox}};%
%
%Page number
\node (page number) at ($(frame.north west)-(0,\headerfirstrowheight)$) [content box,anchor=north west,xshift=\logowidth+\titlewidth,outer sep=6pt] {Page: \thepage\ of \pageref{LastPage}};%
%
%
% HEADER FAUX-TABLE GRID LINES
%
%
%First header row horizontal bottom line
\draw ($(frame.north west)-(0,\headerfirstrowheight)$) -- ($(frame.north east)-(0,\headerfirstrowheight)$);%
%
%Header horizontal bottom line
\draw ($(frame.north west)-(0,\headerheight)$) -- ($(frame.north east)-(0,\headerheight)$);%
%
%Third header column, first row horizontal bottom line
\draw ($($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$)-(0,.33\headerfirstrowheight)$) -- ($(frame.north east)-(0,.33\headerfirstrowheight)$);%
%
%Third header column, second row horizontal bottom line
\draw ($($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$)-(0,.66\headerfirstrowheight)$) -- ($(frame.north east)-(0,.66\headerfirstrowheight)$);%
%
%First header column vertical right line
\draw ($(frame.north west)!\logowidthratio!(frame.north east)$) -- ($(frame.north west)!\logowidthratio!(frame.north east) - (0,\headerheight)$);%
%
%Second header column vertical right line
\draw ($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east) - (0,\headerheight)$) -- ($(frame.north west)!\logowidthratio+\titlewidthratio!(frame.north east)$);%
%
%Second header row middle vertical
\draw ($(frame.north west)+(\logowidth+0.5\titlewidth,-\headerfirstrowheight)$) -- ($(frame.north west)+(\logowidth+0.5\titlewidth,-\headerheight)$);%
\end{tikzpicture}%
}
}