I have and it works without a hitch, at least w/ the dongles I have.
The mp3car dongle uses a completely separate BT stack that interfaces only w/ SD.
I'm thinking about getting some BT devices for the carputer. However as soon as the BT phone support dongle is released for Steet Deck I plan on getting it. Will it be possible to have a bluetooth dongle for other devices as well as the mp3car.com BT dongle for phone support? I can just see this causing problems down the road. Has anyone beta tested this scenario?