For me, amd64 builds would make things easier: I wouldn't have to worry about building 32-bit mesa. I build my own for amd64 since I'm tracking mesa git master for better support for my current graphics card (Radeon rv710; I'm using r600g).
I normally only bother building for amd64 because I don't run much 32-bit code and I don't run it often.
If it's down to sizeof(long), then somebody should have been using int32_t or uint32_t…
… hmm, just noticed
this thread about this. Native is always better.