The Palm OS has (like the Mac) had Bluetooth support for sometime (although only BT 1.2...nto the better 2.0 +EDR)....and like Apple for reasons best known to themselves Palm hadn't included AD2P and AVRCP profiles.
So late in 2004 one of the Palm forums (after making the same discovery that adding bluetooth profiles isn't a hardware thing) launched a challenge to the software community to produce an add on software for the Palm OS to add the missing bluetooth profiles
See
http://discuss.treocentral.com/showt...3&page=1&pp=20 for their journey.
Hey presto and about 11 months later this product was on the market
http://www.softick.com/bluetooth-audio/ and it works...so now all us Palm users have A2DP and AVRCP profiles on Palms and they work great with no added hardware (other than the headphones)
So how about it...someone willing to make this work on a Mac...must be easier...afterall the Linux / Unix drivers exist and the software must be open source...how hard can it be to make an OS X add on?