While the show tends to cater to recumbent trikes and velomobiles, you can expect to find just about any kind of non-standard bike at this well known cycling show.
Press release: http://www.spezialradmesse.de/downloads/ Pressemitteilung2009-e.pdf
Website: http://www.spezialradmesse.de/index.php?welcome
And for those who plan to attend, I'll be there with the O-Trike Silver, answering your questions and offering test-rides.
(edit: Just noticed my LeitraTech appears in the background of one of the 2008 expo photos: http://www.spezialradmesse.de/index.php?tournuser-platz-1
Between the flagpoles and the glass windows you'll see people clustered around my red trike with yellow/red top.)