OK. I'm about to implement something along these lines.

I'm planning on using an ELM323 ( http://www.elmelectronics.com/DSheets/ELM323DS.pdf ) which does all the OBD2 stuff on the car side (ISO in my case) and simply has text commands to interrogate (i.e. the empeg side). Basically it's just a PIC processor with special pre-programmed code inside.

Does anyone else already have any hardware they were planning on using or would like to use? Almost a survey as much as anything.

bjoern (from the other thread), what hardware and software are you using? My code might end up talking to the ELM323 but to talk to your hardware it could be completely a different protocol/commands.

The main issue here is that the empeg will never talk OBD. Instead, it will talk to an interface that in turn talks OBD.