Mmmmph... dunno.
I've never messed with EL stuff... except to buy a nightlight on closeout... it was nice, but
did not last that long. Probably why it was on closeout?
Well, they do that trick WITH LEDs in cell phones!
Maybe you can round up a very dead cellphone and scavenge the rear side of the display??
That's sure to be thin enough!
_-_-
EDIT: they do the same trick on back lit LCD displays too! Another place to look...