The problem seems to be that you can't have multiple domains pointing to a single bucket:
http://developer.amazonwebservices.com/connect/thread.jspa?threadID=27295
Possible workarounds include: - Uploading files to multiple buckets and pulling from them randomly - Uploading files to different buckets and pulling from them with a hash key - Setting a CNAME to point all alternate asset hosts at the primary one - Using Amazon's CDN
Any other ideas? I can't imagine that someone on HN hasn't figured this out already.