A quick Google found
this. I bought something similar in a electronics shop in Hong Kong a couple of years ago. Works great, but of course it is power only. It would be straightforward to hack this into something like Cube did.
I was wondering if Cube was doing something more sinister, like with the OBD port or on the a aftermarket car audio system.
geosynch
I see ck_az beat me to it.... The device above is bascially the same thing.