I guess that might also answer something I've been wondering since this began (well actually before, but this case has brought it back up in my mind). If you take some people skilled in the relevant art, and just describe a problem to them and tell them that someone did solve it but not how it was solved, you lock them away to do a clean room implementation of something that solves that problem, and then their solution happens to be the same as in some patent... then isn't that a bit of evidence that the solution in the patent isn't non-obvious?

Exactly. In fact not only could you say it isn't non-obvious, you might go as far as to say it is obvious.