sleinhash.so is only used in other threads than the one that runs the kernel (does actual solutions search), so no, 64bit will not yield more performance. Skeinhash functions can even be rewritten in pure Python without losing any performance.
Thanks for the info and the miner!

Then there is no reason for the miner to be 3x slower, other than being based on "older" poclbm core with less ATI optimizations?
It is missing the
VECTORS BFI_INT FASTLOOP AGGRESSION
functions that I guess speed things up more for bitcoin in cgminer?
Running at 220Mh/s on a 7970@1170MHz, which runs at 700+ for SHA256 coins.
Only one guy runs anything faster (Anonymous) at the pool, which may be 2 cards, still halfway from 600+ per card.