How could single screen 3DS emulation improve or be reworked beyond the RG cube?

I don't plan to buy it anytime soon but, I've been absolutely amazed by the RG cube's solution to 3DS emulation being having a 1:1 screen. Ever since I've seen I've been wondering what the next 3ds/ds focused device would look like and I'm mostly coming up blank. Bigger screen is obvious, like 3DSxl size but, everything else is a mystery.

Does anyone else have ideas?