I have created an RSS feed for the TextMate changelog which has the actual build (i.e. with the changes) as an enclosure.
The version string contains the build number and can be seen in the about window or by selecting Get Info from Finder.
There's already an entry (in the feed) since the 1.1b17 release. It has some improvements wrt snippets, switching between tabs should be faster, and the problem with bundle items overriding menu keys (like the Insert closing tag) is solved (at least 99% of the time).
Currently these builds are for PPC only and does contain latest bundles from the subversion repository. If you're on MacTel and would like to see an i386 build, add a request in the comments.