You'll find a lot of good stuff if you look through each thread...where they are linked to, etc. etc.
There are several discussions linked within those threads to other forums, including the Vortex for specific discussions on what to do with the Quattro drivetrain changes, regearing, details, etc. A TT mk1 shouldn't be that hard of a swap nor that different from doing a mk3, mk4 or similar. Big considerations do come in with the Quattro models of course and I think a few of them that I have seen have NICELY integrated the MKIV cluster into the TT cluster without much of a problem.
You'll find very few threads detailing specific builds contained in one area. There are very few of us that do it and I can tell you with mine (mk1 mTDI build that I kept a detailed build of the motor, updates, etc. ). It takes ALOT of time to do. Posting pictures, details, etc.
good luck though. I'd like to see more of them. They are around though.
Joe