Very interesting thread, will read over the experiments and results more carefully later, just wanted to add a couple of points I've learned along the way, particularly when simulating for animation.

1. Do it in stages, especially if its a long scene or complicated pose. This could also apply to problems like the seated poses that have given some folks problems. Click through your simulation to find the last "good" frame, use the group editor to spawn a prop, now you have to duplicate your scene and simulate using the new prop. Most importantly you can edit or add to constrained groups, can prevent flattened or sat on areas trying to "swallow" chairs etc.

2. Fake it! Use props to help, in the attached vid I it to appear as if Freak was straining against an invisible layer. It needed 2 shots and 2 simulations, Both made with Freak lying on his back, embedded in a hidden box prop. As BBhas already noted if no verts touch on the cloth and collision surface, the sim fails, so for the freak face shots I replaced nose and other tricky features with scaled down primitives. On another occasion I used spheres parented to a models legs to prevent a dress from falling back too far.

http://www.youtube.com/user/VJflickeringlight#p/u/26/8wawdBTsVTM

Dynamic part in the first few seconds. animated materials are a slight hack of BB's Nacelle shaders