I think S3 is a great origin server for static assets, but it is NOT a CDN. When you click "Upload Media" in PostHaven it stores the media in an S3 bucket: phaven-prod.s3.amazonaws.com
which is great, but it isn't good for delivery. Not only is it slower but it is way more expen$ive.
So here it is Garry, your very own pull zone for phhaven-prod: http://phaven-prod.posthaven.netdna-cdn.com all you need to do is switch it with phaven-prod.s3.amazonaws.com. If you need SSL, I will get it for you Monday.
BTW: The first 10TB's are on us.
curl -I http://phaven-prod.posthaven.netdna-cdn.com/uploads%2F2013-05-17%2F20%2F3128%2FErQE0vKlNMIeNvaxbneY75nWyy4%2Fs3ul27%2Fposthaven-loves-maxcdn.png HTTP/1.1 200 OK Date: Sat, 18 May 2013 00:50:41 GMT Content-Type: binary/octet-stream Content-Length: 52958 Connection: keep-alive x-amz-id-2: NO6o51/19JsQJN9YHc+T/sraZSGNT+f3R+1GWl2QL3aD4SubqazjbMURb4VYaZyS x-amz-request-id: E640348D2D6EDA7B Last-Modified: Sat, 18 May 2013 00:47:10 GMT ETag: "f95534e9752b560f4acdda20228f90ba" Server: NetDNA-cache/2.2 X-Cache: HIT Accept-Ranges: bytes