I’ve also posted a library for diffing/merging/patching written in C#, based on the Perl module Algorithm::Diff. And I posted the source for XPD, the XML pipline document generation engine that I wrote to power GovTrack. These things have helped me; I hope they help you.
GovTrack is now set up on a new server, and it’s much much more responsive than it used to be. In fact, you can’t tell anymore that it’s doing lots of XSLT transformations on each request.