Originally Posted by ForcedInduction

The only way I'd consider an electric pump is to eliminate the mechanical one entirely.

That said, the pump used for the 7.3L Powerjoke is about perfect for our needs. High flow, moderate pressure, simple hose barb inlet/outlet and can be found for around $100.
Wiring is dead easy. An oil pressure switch keeps it on and the glowplug relay bypasses the oil pressure switch to turn it on when the engine is not started yet. Added benefit; loss of oil pressure will cut the fuel supply and stop the engine automatically.