Running packages "in place"

Is it possible to run packages "in place", the same way XEmacs can be run in place? To clarify the question, let me explain how I run XEmacs. I have a directory `~/work/emacs/xemacs-20-hack/', where CVS sources are checked out and hacked by me. There I regularly issue commands like `cvs update', `cvs commit', etc. I compile two versions of XEmacs: an optimized build in `~/work/emacs/build/', and a debugging build in `~/work/emacs/debug/'. (Optimized build is built with `-O3 ...'. Whether error-checking is used depends on my mood and XEmacs stability.) The packages I use are always in `~/work/emacs/xemacs-packages/'. I tell that to XEmacs by using the `--package-path=~/.../xemacs-packages' switch to configure. Now, I'd like to check out packages and use them in place, so that `cvs update' automatically updates the sources I actually use. Is that possible? If so, what do I need to do? The CVS packages contain apparently weird directories like `oa/', `os/', `comm/', etc.