I think these EX70LP Sonys do in fact fit your requirements. Picture is here, including a 360-degree view and zoom-in close ups (if you can get that feature working in your browser, I had to switch to Netscape to get it to work).

Whether or not they will tolerate SLEEPING, I don't know. But they do stay in my ears solidly, and after a little getting used to them, they don't hurt.

The only other alternative would be something where they take an actual MOLD of your ear canal. This would actually be the best for your purposes, but more expensive.