% Tested with beamer 3.07:
\documentclass{beamer}
\usepackage{takahashi}
\usepackage{calc}
\setbeamersize{text margin left = 0pt, text margin right = 0pt}
\begin{document}
\takahashi{Test \onslide<2>{some more}}
\takahashi<1>[label=repeat]{\frametitle{Title here}Test \onslide<2>{some more}}
\againframe<2>{repeat}
\takahashi{$_g$\!\vrule depth.2pt height.2pt \vrule}
\takahashi[]{\frametitle{Title here}$_g$\!\vrule depth.2pt height.2pt \vrule}
\takahashi{\raisebox{0pt}[\height+1pt][\depth+1pt]{!}}
\end{document}
