I have not seen a complete model, but here is some info for parts to make one it is a German site. They have the hull as a kit. I also drilled down into the site bowlman posted and found a running lower hull for you.
http://mmodell.de/forum/index.php?pa...&threadID=7330
http://www.sonderfahrzeug-modellbau....e-tub1-16.html