Seidio makes an excellent car dock for the 6800. Has built in speaker also which makes it perfect for gps with turn by turn voice. I used to use it with my mogul and highly recommend it. Their online store is down but read this page on their corporate site. They have a couple different models and the mount holds a mogul with ANY seidio extended battery or case, AND it rotates to open the keyboard.
http://www.seidio.com/car_kits.html
If I remember they retail for $119. I would be willing to sell mine if anyone is interested.