I don't know of any switch with a light that comes on when its hot. I assume that is something custom.
The melting of the switch is a common problem, and I believe Ford is right that is has to do with replacing the wires with a larger gauge. You may be able to get a switch on ebay or from somebody chopping their car for parts, but since Ford is still selling them I'd jump on it. Also see if Ford can still get the upgraded wiring harness, if not then you'll need to replace the wires individually.
If you don't want to go through all of that then you can simply just rewire the lights using a heavier gauge wire and a switch from an auto parts store. If you don't like the idea of having an aftermarket switch sticking out of your dash you can always hide it under the dash, under the seat, in one of the glove boxes, or even in the ash tray.