You can always upload the .js files to your own CDN. The other magic of CDNs (aside from the potential cache reuse that everyone is talking about in this thead

You can always upload the .js files to your own CDN. The other magic of CDNs (aside from the potential cache reuse that everyone is talking about in this thead) is that the user downloads files from a geographically closer server to them than your server. This is typically a huge speed up, and applies even if your JS files are 100% unique.