One of the very best sources for high end z gauge is Scandinavian Galleries of Napa Valley, CA also known on Ebay as “quality-toys-trains”. Here you will find rare Marklin Z, Freudenreich FR and Modellbau Z along with numerous other items including Marklin sheet metal vehicles. They ship items carefully and fast. I have bought from them for many years without a single problem. Highly recommended Ebay seller.

http://www.scandinaviangalleries.com/