Prestidigitweeze - don't bin your Nexus yet. Have a look at this article:
http://www.synthtopia.com/content/20...exus-7-review/
According to this, Google has managed to get an audio latency of 12ms on Jellybean. Have a look to see if this is you. 12ms is a massive chunk better than 500ms. Of course how they got it and under what conditions might be interesting to explore. On the other hand, your article was pretty old - it pre-dated later Android 4.0+ devices I think yes?
EDIT: Actually my article wasn't that much more recent (confused). Anyway - have a read and see if it adds any hope to the lost cause.