[mediocregopher]

I'll throw my hat in with all the other contenders in here. I've written a tool called goat which wraps around the normal go utility and sandboxes it to a directory, as well as providing versioned dependency management.

It's very simple and easy to use (there's only one new command), and adding it to a project requires no changes to existing code. We've been using it where I work and it's been very effective.

V1 is going to be released soon, check out the current version at https://github.com/mediocregopher/goat