Ecomodded, that just might work. I was going to suggest folks look at the products I just saw on Ebay
OBD 2 II Hud KM RPM Speed Battery Voltage Water Temp Gauge Cluster Hud New | eBay but they don't really cover the ecomodder type of data.
The HUD iPhone app, combined with a new program I saw called Dash Boss could be another alternative...but none as cheap as a cosmetics mirror!~