I'm a fan of that as well. Had not considered using S3 for that. Do you know of a good writeup for handling "?go-get=1" paths differently from html paths in S3? I should likely know this but a quick pointer would be helpful.
The S3 method is kinda experimental. It works for first-level packages but fails for nested packages. We need to look into setting up redirects for those.
We even do it with just an S3 bucket for go.mozilla.org: https://go.mozilla.org/