I do a lot of duo poses in which one character is wrestling with another. I know about collision detection, etc. What I'm wondering is if there is any way to make one character "solid" so that the other character's limbs could touch but not penetrate the first character. I'm probably just dreaming, but that would make things a good deal easier.

I know I can change the display of character parts, or even an entire character, to wireframe, outline, and so forth. And, of course, I can use various cameras and angles to guide me in posing. 

Have I not noticed or realized something? Is there a quicker way to do duel-character poses?

collision detection.
one setting will stop penetration.
check the manual, I dont remember the setting.

I think most people just do it by eye.

 OK. thank you. I'm checking it out right now. I have just been doing it by eye.

The problem with collision detection is that it will slow down your application.  It is not quite as instantaneous as you would like it to respond.

Collision detection also does NOT work in an animation.

Boy, that's for sure. It locked up the program and I had to force quit. I'm going to try just "show collisions" next and see if that's any better.

What I'd really like –– and maybe this is just a wild dream –– is a "wrap around" function, so that an arm could wrap around another character without penetrating the other character's mesh. 

collision detection on and full tracking mode with texture display is a recipe for a VERY VERY slow system. I suggest switching display mode to smooth shaded , and tracking mode to box. That will reduce the load.

 Well, for the close up poses I'm doing, probably the way I've been handling it –– by eye, will work best, at least for me.