How can I push footnotes to the bottom of the page in beamer?

Question

In beamer, footnotes appear at the bottom of the slide, but above the footline. However, the theme that I'm using has lots of empty space on the left side of the slide that would be perfect for showing these footnotes. Is there a way to position the footnotes in beamer such that the bottom of the lowest footnote is always at the bottom of the page?

\documentclass{beamer}
\usetheme{Warsaw}
\begin{document}
 \begin{frame}
  abc\footnote{\color{red}foo}
 \end{frame}
\end{document}

That code produces this:

but I'd like to modify it to produce something more like this:

(it looks ugly in this case but that's just for demonstration purposes).

Answer 1

Depending on how many footnote you have, you can use textpos to emulate a footnote like this:

\documentclass{beamer}
\usepackage[absolute,overlay]{textpos}                    % new package
\usetheme{Warsaw}

\newenvironment{reference}[2]{                            %
  \begin{textblock*}{\textwidth}(#1,#2)                   % This is the code
      \footnotesize\it\bgroup\color{white}}{\egroup       % for the emulated
  \end{textblock*}}                                       % footnote environment


\begin{document}
 \begin{frame}

  \begin{reference}{10mm}{93mm}                           % this is the code used inside a                      
  $^1$foo                                                 % frame to state the position 
  \end{reference}                                         %   of the footnote

  abc$^1$

 \end{frame}
\end{document}

which produces this:

knowing that a beamer slide is 128*96mm in size you can place text pretty much anywhere with this method.