I have been thinking about this for bout a week now
If the keys are the same size on the XPS M1730 keyboard it might be worth getting one of those keyboards off ebay and seeing it u can pop off the keys and pop them on your E1705/9400/M1710 keyboard.
That would give u translucent keys at least, then you could try thishttp://highlandsun.com/hyc/LumiKey/
electroluminescent sheet idea, after that its just a small question of where you get the power and put the driver for the EL sheet
I thought you could hook it into the power for a usb port but i dont think they provide enough power,
I am going to try all this one day but until then it would be nice if any one with both a E1705 or M1710 and a M1730 could tell me if the keys are the same size
Failing that im going to get a mate who works at a plastics factory to order me some transparent thermosetting plastic, then i will mold them myself