I don't teach photography, but I mentor teachers daily at work and have worked with some over the net from else where in the states. For your request, I think there are two avenues you can follow to get the help you need.

Ave. 1- There are lots of very accomplished photogs on this site, not just "good photographers" but people who have been around the block a while and have made a bit of a name for themselves. Seek these folks out, PM them with a request, and don't give up if the first turns you down. Keep going. They are not going to be able to give you a face to face sit down discussion but you can mail them several prints for them to judge then have a chat in the chatroom here or on something like Instant Messenger. Not very personal but might get you what you need. As you work and discuss more prints can be sent and more exchanges made. I would not rely on website viewing of your work. Nothing compares to the real thing.

Ave. 2- Move to where the person whom you want as a mentor practices. Some folks would say this was a bit of a stretch but it happens all the time, especially in photography.

As for the unknown unknowns which keep you from saying what it is you want to learn this could be hashed out with the person who agrees to mentor you after they see your portfolio.