You could pull the IrDA interface - this goes to an IrDA encoder chip (due to bugs in the SA1100's internal irda encoder). You're then left with a 3.3v-level serial port that will go up to 230,400bps - ideal for bluetooth.

I believe the bluetooth support from Axis for the linux kernel *only* works with serial bluetooth adaptors at the moment - bluetooth over serial is one of the defined methods to talk to a bluetooth transceiver embedded in a system. The Axis stuff allows at least a modem connection, I think.

http://www.blueunplugged.com has modules designed for embedding (see the "development" section) for UKP 85+VAT. Real, external serial modules that are a bit more robust aren't a lot more, though.

Hugo
(who's just got a T68 with bluetooth, replacing his 6210+bluetooth battery)