There's actually a couple extra spots in my cluster face that have blank bulb sockets on the back side. The bulbs for the dummy lights are all clear, so are the plastic w/ the symbols printed on them. There's just little bits of colored plastic in there so the engine light is yellow, and the highbeam is blue.
Wouldn't be to hard to rig something like that up...except I have no Vtech, my man. And I don't need a light that kicks on when your vtech hits.