How should people (in general) track .kitchen.local.yml with it in the .gitignore? 

Either way, I'd rather see primary maintainers shipping .kitchen.yml where the Real Tests were actually performed. In this instance, kitchen-ec2 is being used to test Amazon Linux, has enough subtle differences from Centos to warrant a real converge and integration test. It is impossible to test Amazon Linux outside of Amazon. The same thing will be true for SmartMachines, once a kitchen-joyent driver is written... AIX on an IBM cloud, etc.

-s