Instead of using hosts to front the EC2 mirrors, we should move our mirrors to being hosted on S3. There are numerous advantages to doing so -- most notably speed, lower costs, lower maintenance costs, access policies, etc. Using S3 also realizes some cost-savings for Canonical since all intra-zone transfers are free.
Summary: 1. New mirrors would be setup in each region 2. Scripts would need to be updated to use regional mirrors 3. DNS names would need to be updated