The unit I bought was very similar to this, but without the OBD connector:
http://cgi.ebay.com/ebaymotors/Heads-Up-Display-MPH-HEAD-UP-Head-Up-Vehicle-Speed-_W0QQcmdZViewItemQQhashZitem19c1175f40QQitemZ11061 3716800QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries#ht_4736wt_893
It required splicing into the speedo signal (from behind the radio), the tacho (from OBD), illumination (radio), 12V and ground. It also comes with a water temp sensor, which I haven't connected. I might use it for oil temp instead at some stage.
My car is off at the painter's coz some woman reversed into my car and then fled when my car was parked (from a witness). I will take some pics when I get it back.
I installed it a year ago. But never quite finished it. I wanted to bury the display unit under the dash, requiring me to cut a hole into that long plastic dash trim near the windshield. Never got around to doing that. So the unit just sit on top of it for now. Fully functional though, just not as integrated looking.