I have created a few commands that are analogous to the Subversion commands which diff against a revision, but instead of generating a diff output, the result is sent to FileMerge for viewing, which IMHO is a whole lot easier to read.
Could you possible release the actual bundle or bundle items?
So us lazy people don't each have to redo all this stuff.
If this stuff really works well, let's just add it to the official TextMate bundles.