Yes, we had a last minute issue with the 64-bit builds, they will be available in a few hours.
Are you seeing any performance difference in 32 vs 64? I'd imagine the vast majority of newer Windows PC that ship can do 64, but is there a great reason to run 64-bit VLC?
AFAIK we didn't do an actual benchmark but when doing software decoding/encoding there should be small improvements here and there.
64bits gives you more registers (very good for codecs), but has longer pointers, so does not help too much for your cache misses.