I'm writing unittests for a program I'm writing, and would really love to be able to use captured_stdout/stderr.  Of course, I have to support Python 2.5, and can't really justify installing unittest2, so I'll have to roll my own anyway, but I'm definitely +1 for those functions to move into unittest.  A bunch of the others, too, but that's the one I just looked at, and the API looks good to me.  (I'd rename captured_output and leave it be an implementation detail.)

How about 'tools' for the submodule name?