I think the nan issue you are referring to was caused by some weird stuff with Bazel.

I put together an AMI in virginia: ami-cf5028a5 and if you have a masochistic streak, here are the steps to do it yourself: https://gist.github.com/erikbern/78ba519b97b440e10640

The main issue I'm still seeing is that g2.8xlarge with my AMI doesn't run 4x faster than g2.2xlarge even if correctly detects the 4 GPU's. Haven't had time to identify the issue though.