Yea, the basic reason for not just using a python script is that I want to consolidate them :) We have a couple of python scripts laying around and I'd like everything to be available and discoverable from within invoke. It's also just the first step. Ideally we'll end up with a number of tasks that automate the various processes we have around pip, including releasing, and have it all done in one central location.

I talked to @bitprophet and he said that he's not planning on doing any Windows support himself, and he's not willing to seriously hamstring the invoke code base to support Windows, but that patches are welcome. He recognizes that Windows is a sizable minority but is unable to do the work himself. So if it becomes a problem in the future where we need Windows support we have a path forward where we can contribute patches to invoke.

By the way, I know it's less than ideal but we also have 2k a month worth of free servers too. If you want a persistent Linux box for dealing with pip on *nix I can spin one up for you. (They also support Windows servers, i've used them from time to time to test stuff on Windows).