Yes, that can be done. In fact, Stangrcr1 has done it. But, his gauges are reading low, so apparently it needs to be bit more than 5.0 volts. In fact, it may be that Ford was right that it needs to be 5.5 volts. However, what I plan to do at some point is to document the various resistors the factory manual says are required to calibrate/test the gauges, collect said resistors, and find a set of gauges that work as they are supposed to work. Then I'll use a variable power supply to determine what DC voltage it takes to replicate those readings.

At that point I could build solid state ICVR's that would give the readings the gauges are supposed to give, assuming the sending units are correct. Or, I could just buy one off of ebay for $24.50, but so far all I've seen on there for our trucks are units fixed at 5.0 volts.