Hi Mike,
Yes, I'm eager for 64 bit as well, and at this point it's on the front burner. The 3.0.11, and now the 3.0.12, releases have been higher priority, since they addressed two important bugs that were affecting Vista and CS4.
I now have the hardware and development tools in place to make it happen - now it's time for the "knitting" needed to get things compiling in the new environment, and tested. Bit of a jump, but on the other side will be a definitive solution for folks with > 150 Mb images.
I have not noticed much of a performance jump with 64 bit PS. OTOH, I have not done any careful benchmarking - it's mainly an issue of handling larger images.