Ho provato a modificare il codice ma il risultato non è stato dei migliori! Ho poi trovato un link su di una guida qui pubblicata in cui si può creare un tema a mano (http://titilog.free.fr/indexEng.htm):
`\ProvidesPackageRCS $Header: /cvsroot/latex-beamer/latex-beamer/themes/theme/myTheme.sty,v 1.0 18/12/2011 23:08:20 G.FALLOURD-M.LEBRETON Exp $
\mode
\definecolor{subsectionColor}{RGB}{0,0,102}
\definecolor{sectionTextColor}{RGB}{0,0,0}
\definecolor{subsectionTextColor}{RGB}{255,255,255}
\definecolor{leftFootlineColor}{RGB}{130,36,51}
\definecolor{middleFootlineColor}{RGB}{130,36,51}
\definecolor{rightFootlineColor}{RGB}{130,36,51}
\definecolor{authorColor}{RGB}{255,255,255}
\definecolor{footlineTitleColor}{RGB}{255,255,255}
\definecolor{instituteColor}{RGB}{255,255,255}
\definecolor{dateColor}{RGB}{255,255,255}
\definecolor{pageColor}{RGB}{255,255,255}
\definecolor{titleColor}{RGB}{255,255,255}
\definecolor{titleTextColor}{RGB}{130,36,51}
\definecolor{bodyColor}{RGB}{255,255,255}
\definecolor{normalTextColor}{RGB}{0,0,0}
\definecolor{exampleTextColor}{RGB}{51,153,51}
\definecolor{alertTextColor}{RGB}{204,51,51}
\definecolor{chipColor}{RGB}{0,0,102}
\definecolor{chipTextColor}{RGB}{255,255,255}
\definecolor{normalBlockColor}{RGB}{255,255,255}
\definecolor{normalTitleBlockColor}{RGB}{130,36,51}
\definecolor{normalBlockTextColor}{RGB}{0,0,0}
\definecolor{normalBlockTitleTextColor}{RGB}{255,255,255}
\definecolor{exampleBlockColor}{RGB}{0,204,0}
\definecolor{exampleTitleBlockColor}{RGB}{0,153,0}
\definecolor{exampleBlockTextColor}{RGB}{255,255,255}
\definecolor{exampleBlockTitleTextColor}{RGB}{255,255,255}
\definecolor{alertBlockColor}{RGB}{255,153,153}
\definecolor{alertTitleBlockColor}{RGB}{204,51,51}
\definecolor{alertBlockTextColor}{RGB}{255,255,255}
\definecolor{alertBlockTitleTextColor}{RGB}{255,255,255}
\setbeamercolor{section in head/foot}{bg=sectionColor, fg=sectionTextColor}
\setbeamercolor{subsection in head/foot}{bg=subsectionColor, fg=subsectionTextColor}
\setbeamercolor*{block title}{fg=normalBlockTitleTextColor,bg=normalTitleBlockColor}
\setbeamercolor*{block body}{fg=normalBlockTextColor,bg=normalBlockColor}
\setbeamercolor*{block title alerted}{fg=alertBlockTitleTextColor,bg=alertTitleBlockColor}
\setbeamercolor*{block body alerted}{fg=alertBlockTextColor,bg=alertBlockColor}
\setbeamercolor*{block title example}{fg=exampleBlockTitleTextColor,bg=exampleTitleBlockColor}
\setbeamercolor*{block body example}{fg=exampleBlockTextColor,bg=exampleBlockColor}
\setbeamerfont{block title}{size={}}
\setbeamercolor{titlelike}{fg=titleTextColor,bg=titleColor}
\setbeamercolor*{normal text}{fg=normalTextColor,bg=bodyColor}
\setbeamercolor*{example text}{fg=exampleTextColor}
\setbeamercolor*{alerted text}{fg=alertTextColor}
\useinnertheme{rounded}
\setbeamercolor{item projected}{bg=chipColor,fg=chipTextColor}
\setbeamercolor{author in head/foot}{bg=leftFootlineColor, fg=authorColor}
\setbeamercolor{title in head/foot}{bg=middleFootlineColor, fg=footlineTitleColor}
\setbeamercolor{institute in head/foot}{fg=instituteColor}
\setbeamercolor{date in head/foot}{bg=rightFootlineColor, fg=dateColor}
\defbeamertemplate*{footline}{infolines theme}
{
\leavevmode%
\hbox{%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
\usebeamerfont{author in head/foot}\insertshortauthor~~
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
\usebeamerfont{title in head/foot}\insertshorttitle
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
\usebeamerfont{date in head/foot}\insertshortdate{}\hspace*{2em}
\insertframenumber{} / \inserttotalframenumber\hspace*{2ex}
\end{beamercolorbox}
}%
\vskip0pt%
}
\mode
Certo non è il massimo della personalizzazione, ma meglio di Warsaw!