I've found that Classic Industries sells a "Low Fuel Warning Module" on pg. 77 in their latest Camaro catalog.
CJ, you might be able to adapt this module to work with an aftermarket gauge.
A possible answer to my question I posed earlier: the light bulb in the factory low fuel module may have been a pre-production design meant to fit into a different gauge bezel than was actually used. The bezel may have changed without changes made to the module. Factory assembly workers, not having a place to snap this into, just dumped it into the rest of the console wiring.