After 'go get'ing the package, you can use git/hg/bzr to checkout the specific version you want. From there, all of the Go build tools will work as normal.

I don't think so, but I could be mistaken. (btw, someone pointed that out as a drawback on another thread.)

What I've done sometimes is just clone the repo within a directory that appears in the GOPATH, maybe checkout a specific revision, and that solves the problem.