thanks for passing on your experience. I found it constructive.
I think I know what is causing the problem and so I believe I am close (a couple more days) to fixing it.
The attached image confirms I was able to reproduce the problem with a JMatch on my Moodle 1.9 site. It also show that the new version of the HotPot module, which will probably be part of Moodle 2.0, fixes the problem, because it is able to separate the Moodle styles and page layout requirements better from those of the quiz.
out for now