A much needed topic indeed, Did you have any problems with recompiling the code that calls the procs? It seems that by renaming the proc, you now have to go out and find all the places that use the proc and update the name there too. As brbolte mentioned, this may be perfect when you don't want to break existing code, but for the stuff that we do, I would have to then modify dll's and redistribute the dll's to the team members, a lot of work, and it seems to me reduces one of the great qualities of SPs, the fact that you can encapsulate logic and just update the db instead of redistributing executables.
I will share my method, which is also some work, but perhaps less depending on the environment you are in. We use CS-RCS, and just use the scripting tools of Query Analyzer to save off a copy to be versioned. I think this would be more difficult in the hectic nature of the project you were on, but it works well, especially tracking changes as they migrate to a centralized testing db, or even just to production. The nice thing about using a revision control system is we can quickly see history and perform diffs on the files to see what is going on.
my 2 cents.