OK, cmd/tests it is. I've updated http://kegel.com/wine/sweng/2010/#tests accordingly.
A rough prototype is at http://kegel.com/wine/cmd/tests/ (I'm doing this all on a tiny netbook which doesn't have a wine development system, so I can't produce a patch yet.)
To-do list: - fix http://bugs.winehq.org/show_bug.cgi?id=21144 so we can more easily compare output of wine's cmd with output of windows' cmd - integrate into wine's build system - bundle the test scripts with resource calls instead of escaped arrays - better messages on test failures? - alternately, move to one test script per bug? - coax winetest into including this binary, and make sure they work well together