I've finally managed to contact David Lister, who is a founder member of the British Origami Society and one of our distinguished origami historians. He is very interested in Troublewit and has done a lot of research on it, as have a number of other origami aficionados. He has an written an article on the subject, which is as yet unpublished. It's a bit long to post here, even though David stresses it's just the tip of the iceberg, but I can pass it on via PM to anyone who's interested (just let me know).
In answer to Andrew's original question about the origin of Troublewit, David says he has found no convincing evidence of it being invented in China or brought back to Europe by Pre Mathieu. He doesn't completely discount the possibility of a Chinese origin, but suspects it may have been a showman's ploy to add mystery to his performance.
One of the things David mentioned is that the ancient art of tablecloth folding has been revived just recently by Joan Sallas, a Spanish paperfolder who lives in Germany and has done a lot of research into old German paperfolding books. He has recreated some of the tablecloth folding designs described in the "Trincirbuch" and mounted exhibitions in Germany. The exhibition catalogue is still available here:
If you enlarge the Contents page, you can see there's a short chapter on Troublewit.
David also mentioned some articles by Roberto Morassi in the Italian origami magazine "Quadrato Magico", from 1984. I happen to have these, and he goes into some detail about both Troublewit and tablecloth folding, with references to the Italian book that preceded the German "Trincirbuch". It would be rather a lot to translate, but I could summarise the information for anyone interested.
There's another origami book by Yoshizawa which has some pleated paper folding in it, called "Origami Sosaku" (Creative Origami). Not much, and it's his own version again, rather different from the standard Troublewit. For one thing, the figures are static (vases etc.). Available here for anyone interested:
http://www.origami-shop.com/en/akira-yo ... -1291.html
I also found some more Hofzinser pictures showing him with Troublewit:
Running out of time again. For anyone who's still with me, I hope it was worth the wait.