[Prestidigitweeze]

I'd like to know more about the OP's size requirements. Weren't the only other covers with built-in lights the ones made by Sony, and isn't the only reader for which you can still find such a cover the PRS-350?

Apparent Requirements Met by the PRS-350:

ePub?: Yes.
Cover with light?: Yes (if you're willing to go on an Easter egg hunt or are fond of pink).
Size?: Who knows?

That said, how can we recommend an exact replacement for a type of reader that hasn't been in production for years? Tell us where you're willing to compromise, OP.