Good point, but in practice, if someone asks me to read a USB stick, it would be a bit awkward to pop the back plate of the phone, stick in the Mobidapter and the USB stick, and somehow hold the device so the screen is visible without the Mobidapter falling out and damaging the connector in the process. What I could imagine working is if you jury-rigged a ribbon cable connector from the Mobidapter that could then be fed into the n900 internal connector. Still would look pretty Frankenstein-ish, though.

The idea of a BT to USB adapter, if one exists, sounds much better.