This is just my opinion, but in spite of your difficulty in finding a satisfactory instructor, I still think a few one-on-one lessons are the way to go. If you live near any medium-to-large-sized city, there must be a teacher with whom you would get along. Maybe it’s just a matter of looking in the right place. Try asking around at your local music stores.

Especially for working on rhythm guitar playing, as you mentioned, you need immediate feedback from the instructor—saying “No! That’s not it! Stop rushing! Tap your foot, damn it!” or “Yes! That’s it!”—as he watches your hands, feet, and body, and plays along with you in real time. It’s hard to make that happen online.

Look for somebody who has most of these things:
-is formally educated in music with at least a year at Berklee, MI, or a university,
-is articulate and a good listener,
-is drug-free,
-has played lots of different kinds of gigs,
-is commercially published, or has some charts and/or handouts that he’s accumulated for teaching purposes. This shows a commitment to teaching.
-keeps track of your lesson activities
-gives homework, especially when he sees you lack focus.

It’s not really necessary that he’s an astounding player, unless you’re desperate for that kind of inspiration.

Lots more tips at Barrett’s http://monsterguitars.com