I am no expert. (And, you might want to tell me to STHU.) But that seems counter productive. The Nanocube dimensions are optimized for your viewing pleasure with it's bowed cornerless front. Aside from that, most proven sump designs are for long-ish aquariums. You may not want to experiment with unproven sump dimensions. Though, eshopps seems to be experimenting with cubes lately. So, that would be a start.
In any case, best of luck.