\mode<presentation>
\useoutertheme{miniframes}

% No headline.
\setbeamertemplate{headline}{}

% An optional command that will appear in the middle of the footer.
\defbeamertemplate{footextra}{}

% Stolen from the miniframes theme, and modified to include the
% footextra template.
\setbeamertemplate{footline}{
  \begin{beamercolorbox}[colsep=1.5pt]{upper separation line foot}
  \end{beamercolorbox}
  \begin{beamercolorbox}[ht=2.5ex,dp=1.125ex,%
    leftskip=.3cm,rightskip=.3cm plus1fil]{author in head/foot}%
    \leavevmode{\usebeamerfont{author in head/foot}\insertshortauthor}%
    \hfill%
    \usebeamertemplate{footextra}%
    \hfill%
    {\usebeamerfont{institute in head/foot}\usebeamercolor[fg]{institute in head/foot}\insertshortinstitute}%
  \end{beamercolorbox}%
  \begin{beamercolorbox}[colsep=1.5pt]{lower separation line foot}
  \end{beamercolorbox}
}