E-ink can be backlit, there is a new reader out there that is backlit. I think it boils down to how they come off the line, if they come out as 4x6 screens, we can forget about sizes that we want, but if they come out of the manufacturing process as a long strip that is cut to length, we might have a chance.
I do think it that a 16:4 backlit color e-ink marquee would be perfect, as marquees are mostly static, only changing when the game changes.