Here is a quick try with Tikz:
\documentclass{standalone}
\usepackage{tikz}
\newenvironment{itemizewithline}[3]{%
\newcommand{\itemwithline}[1]{%
\begin{tikzpicture}
\node (box){%
\begin{minipage}{\textwidth}
\item ##1
\end{minipage}
};
\coordinate[shift={(-\itemsep,-0.75em)}] (boxne) at (box.north west);
\coordinate[shift={(-\itemsep,0.25em)}] (boxse) at (box.south west);
\draw[\colorhook] (boxne) -- (boxse) -- ++ (0.2,0);
\end{tikzpicture}
}
\edef\colorhook{#1}
\edef\titletext{{#2}}
\edef\subtitletext{{#3}}
\begin{tikzpicture}
\node (box)\bgroup
\begin{minipage}{\textwidth}
\begin{itemize}
}{%
\end{itemize}
\end{minipage}
\egroup;
\node[anchor=south west,color=\colorhook] (title) at (box.north west){\titletext};
\node[anchor=west] (subtitle) at (title.east){\subtitletext};
\draw[\colorhook] (title.south west) -- (title.south east);
\coordinate[shift={(2em,0)}] (hookstart) at (title.south west);
\coordinate[shift={(0,0)}] (boxsw) at (box.south west);
\draw[\colorhook,line width=1.5pt] (hookstart) -- (hookstart|-boxsw) -- ++ (0.2,0);
\end{tikzpicture}
}
\begin{document}
\begin{itemizewithline}{red}{Title}{subtitle}
\itemwithline{one}
\itemwithline{two
three
four}
\itemwithline{five
six}
\end{itemizewithline}
\end{document}
The result:
