I think I remember you talking about this some with a poll that I started a while back. It was interesting. I've since been thinking of making a project of taking and posting pictures of body parts for reference, like I did with the hands some time ago. Hands, feet, knees, elbows, back, etc. I just worry that it'd look exhibitionist or attention hungry.

A model who is old, heavy, out of shape, or otherwise not the physical ideal can be a great subject. There's some things about how the body changes and weathers that you can't learn from anyone else, and it broadens your artistic repertoire a lot.