I'm an EE and I'll try to help. However, I've never played with the electronics of fuel gauges.

First off, are you sure using the Omega symbol is correct? In electronics, the Omega means "ohms", or resistance. Variable resistance is rarely used in this type of application. Instead, typically they use voltage (or V). I know that Autometer gauges all use voltage levels for readings; and O2 sensors, and other sending units produce voltages.

Ok... so it is possible to build a translation circuit. Personally, I don't think it's worth it, unless you're doing this purely for a hobby sake.

You will not be able to mod the gauge itself. (Well theoretically you could, but that's REALLY not worth it.)