As for the unused usb port and bluetooth, yes, it can be done. I modded an 867 Ti with a usb hub with bluetooth 3.0 and wifi N and yes, it does read in 10.4.11 just fine. sure, they are usb 1.1 spec, but both dongles get 500ma per device and they both connect and run just fine. As for fitting them into the laptop, i took out the old airport connector and the PCMCIA assemble, and they have lots of room. Taped down and electrical tape on the bottom cover to prevent electrical short.
*edit* proof it can be done