Thanks to Ben Howard and support from Canonical IS the Ubuntu S3 mirrors are now globally available.
I’ve been using the east-1 mirror for a while now and it’s nice to have a mirror that can saturate your bandwidth. If you’re looking to use these I’ve written out all the mirrors in this answer by region if you want to just copy and paste it in your
/etc/apt/sources.list or your Software Sources and hit that regional hotness.
Of course if your instances are running in AWS already then you have region-local mirrors so you’re already enjoying LAN-speeds.