Your script is pretty much the same as mine, good to see :) For everyone who wants to give it a try and wants some instructions http://simonvanderveldt.nl/boot2docker-on-xhyve/

I've also done some quick benchmarks, they are at the bottom of the post. Virtualbox had about 50% higher disk IO performance in my measurements.

Regarding the root permissions for networking: As far as I know it shouldn't be necessary if you sign the xhyve binary, haven't tried that though.