I’m currently working on an AmbiCom Air2Net BT2000 driver for Blunt (thanks for the loaner, Zac!). It is highly likely that this CompactFlash card will be supported without restrictions. So we have the PICO Card, the internal modules, and now the BT2000 card. The BT2000 card is not very expensive and consumes very little power. It looks like a good choice if you are living in the US since it is readily available there. For Europe, the PICO cards show up regularily on eBay, but I suspect that the Conceptronic Bluetooth CF cards could work as well.