regarding cluster coding, we're fairly new to the endeavor. From what I've found,
Jetta,97 on the VW TDI forum is the officionado of cluster swap, recoding. He's professional (not free), but the forum is RIDDLED with great feedback of his work. I believe that the AUDI cluster dumps are sufficiently similar to VW that he'll be able to help you out.
There's also
old_no7 of UK-mkiv's, he's prolly less stingy with sharing the info, and seems comparably as knowledgeable on the inner workings of the VAG cluster.
cheers, and please let us know what you learn or figure out.
-Cyril