From what I've been reading, it's not needed - due to the way OSX is built, 32 bit processes can address 4GB already.
Ben, just a thought, I have been working with Digital Audio Workstations (DAW) programs forma while and have seen the transition from 32 bit to 64 bit. Many of the virtual music instruments which were. Originally written 32 bit were unusable in the newly written 64 bit DAWs until someone wrote a program called JBridge. This program allows you to use a 64 bit dll in a 32 bit program and a 32 bit dll in a 64 bit program. It provides a skeleton that does the conversion.
Is this usable at all. Are these libraries written as dll?
I may be totally wrong here. Just a thought. BTW i have JBridge. i think its like 30 bucks.