This is insane. I am the FW800 user. I decided not to BTO my DP1.25Ghz due to the slowness (a couple weeks to wait). They listed the module at $50 in the AppleStore, but I checked their service and parts site.. it costs $178 as new. I think this included the labor, but heck... what's wrong with Apple.
I know there is a D-Link Bluetooth adapter for $50, but why take up an USB port if the machine is bluetooth ready, like AirportExtreme.