A ScanGauge with RPM/Speed display
 

I hope they can be convinced to add a selectable display item for the overall effective gear ratio of the engine/transmission/wheels.

Engine speed in RPMs divided by Speed in selected units

RPM/KPH or RPM/MPH depending on settings

Very useful for the slushbox crawd because you can see lockup and lsippage rates pretty easily and it wouldn't be too hard to add I don't think.

OGR? Overall gear ratio?

Or possibly GRM for miles and GRK for kilometers - not my call, but I really want one with that on it.