change margin on beamer title slide

Question

I want a wide right margin for most of a presentation using beamer. I can change the margin for all beamer slides like so:

\documentclass{beamer}
\usepackage{lipsum}
\title{A title}
\author{The author}
\setbeamersize{text margin right=5cm}
\begin{document}
\maketitle
\begin{frame}
\lipsum[1][2]
\end{frame}
\end{document}

Is it possible to change the margin for the title slide? I would like the title, author and date to be horizontally centered (so in effect, no wide right margin for the title slide but a wide right margin for all other slides).

Answer 1

Based on Gonzalo Medina's answer, I have come up with this which seems to work:

\documentclass{beamer}
\usepackage{changepage}
\usepackage{lipsum}
\setbeamersize{text margin right=5cm}
\setbeamertemplate{title page}
{
  \begin{adjustwidth}{0cm}{-4cm}
    \vskip0pt plus 1filll
    \begin{centering}
      {\usebeamerfont{title}\usebeamercolor[fg]{title}\inserttitle}\\
      {\insertauthor}\\
      {\insertdate}\\
    \end{centering}
    \vskip0pt plus 1filll
  \end{adjustwidth}
}
\title{A title}
\author{The author}
\date{1 January 1900}
\begin{document}
\maketitle
\begin{frame}
  \lipsum[1][2]
\end{frame}
\end{document}