Actually there is such a thing. Not sure if it's what you want, but HKS made the Camp System. I helped put one of these in a buddy's WRX awhile ago. We used the video output of the Camp module to the Aux in of the in-dash dvd. It was able to display air/fuel mix, EGT, O2 and a bunch of other info. Only downside is the system is pricey and each extra sensor was priced seperate. Well atleast they were at the time, and this was atleast 6 years ago.
Here is an article I found when I googled HKS Camp System
http://www.turbomagazine.com/tech/turp_0809_hks_camp_2_fuel_management/index.html