RSScache.com: Here’s a free service to cache your RSS feed which we’ve talked about here and here. This site subscribes to your RSS feed, then translates that into a much narrower one for dissemination to end users. Users subscribe to the feed through this site, instead of through your actual site (how would you enforce this? thought a redirect, perhaps?).
It’s free, but they tack a little link into the bottom of each entry which refers people to their service. I think the idea is to actually sell the services to “enterprises,” but why wouldn’t they just use the free service? If you proxy their URL, you could even make them do all the work without anyone knowing about them.