Any idea if the Turtle Beach Audio Advantage Micro could be made to work on our tablets? The audio quality on the N810 isn't so hot, and this'd make for a really nice improvement.

Maybe. A number of people have tried various USB sound cards, but AFAIK no actual reports of complete success.

From what I've heard, the main problems with the output are from the touchscreen sounds (disable these, as they're 8kHz, and the 8kHz-with-noisy-resampling channel stays open some seconds after they're played), and from impedance mismatch with some phones; using a good headphone amp is said to help. IDK; it's fine with my ARE05's, but then my ears can't tell a coat-hanger from a high-quality cable either.