Most proxy sites get blocked so I really wouldn't say there are that many loyal visitors over a long time.
Nice read though, I'll have to take a look at some of those CPM companies you said allow proxy sites as I'd like to get rid of my Adbrite ads.
Also in your "Monetizing proxy sites" article you say Adsense allows 3 ads when its really 4 (3 content, 1 link bar). Just thought you might want to know