I've been using a service by unblock-us.com, which provides a proxy to Canadians/others allowing access to services that are locked down to only US ip addresses.

This is easy enough to achieve by setting up a reverse proxy (eg: squid) on a US-hosted server, and then configuring your browser or OS to use that proxy.

However, there is something that unblock-us does that I'm not sure how to duplicate. Rather than configuring your OS to use them as a proxy, you can simply change the DNS Server settings on your router to point to their addresses. Any requests to services they support are automatically proxied. The advantage to this is that you don't have to set up every computer in your house, and it "just works" with clients like ps3, xbox, android, etc. Disadvantage is you really don't have control over what gets proxied, as well as there are privacy concerns I suppose.

How can I achieve this same functionality on my own us-based slice?