Bluetooth evil deeds
Bluetooth usb sticks that take rp-sma antennas. Found on ebay and elsewhere.

And on a related note, the below is a presentation of an attack on a Bluetooth enabled headset.
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Papers of interest:
on September 28th, 2007 at 7:57 am
http://dc4420.org/files/dominicgs/bluesniff_slides.pdf
more on sniffing bluetooth with GNURadio