this is one mod I would seriously love to do... I read somewhere about someone doing a custom unit with a small monitor and an angled mirror in the dash, but I can't seem to find it anywhere.
Umm this would be very interesting - if the unit isnt too big would fit nicely behind the speedo cluster - and wiring would be dead easy to hide from the OBD socket - straight up out of the bottom of the A-Pillar - which is what i did to hardwire my Road Angel.
Agreed - only a single cable needed from the OBD2 socket. Just getting a HUD unit that displays what I want seems to be tricky. Ideally, speedo and revs is what I need.