The issue is fairly simple and complex at the same time. The OS provides the bluetooth stack and maintains the connection status. Now there are (wierd) things that cost one arm (no leg) which are "paired devices" but is this worth a few hundred to solve?
Example unit I'm using to bluetooth link some serial devices at http://www.ipenabled.com/bluetooth-rs232.html and the price seems to go up from there.
So let's see what others have to offer.
I have a G-5 Tower 1.6, 2Gigs, built around 2005. I installed a Airport Extreme card which works great. I use an external bluetooth adapter. My problem is when I boot from a disc such as Drive Genius or any of the utilities that have boot capability the computer loses its bluetooth signal when it goes through the shutdown startup procedure. I end up always having to use a wired mouse and keyboard in order to complete my operation.
My question is if I install a bluetooth card in the computer will I still have the same problem? I have a G4 laptop and of course never have this problem as it has a built-in bluetooth and airport extreme.