Well... Here's a picture of how far you can get without color filters.
Notice the rich blue color that the sill come in, which is probably why not too many people have tried to switch.

The EL panel next to the door sills is the color of "green" EL panels (really indiglo blue-green).

But there is some green light emitting from it, so it would be possible to get these panels to appear an almost true green with a color filter. Whereas the stock blue EL panels emit almost no green light, hence why people failed at making them appear green.

If you want to purchase the door sills, but are afraid to ruin them, first practice on your original (non-illuminated) sills. They are nearly identical in construction.