> What do you think about the following (requires the verbatim package):
>
> \newcommand{\zzTop}{\vspace{-2\parskip}}
> \newcommand{\zzBot}{\vspace{-1\parskip}}
> \newenvironment{tightverbatim}
> {\zzTop\verbatim}
> {\endverbatim\zzBot}
>
> I'm also thinking about putting a -1\parskip between theorems and proofs.
If it works, fine with me. As you can see from my horrible code, I didn't have
a better solution :-).