If you can fit 35's or larger this is the best mud tire out there.
http://www.maxxis.com/products/automotive/product_detail.asp?id=64

We were in some deep off camber mud and all Linda (Driver) could compare them to was chains. Some of the other Maxxis team members were out in the mud compairing them to rigs with MTRS and SSR's and the Maxxis were hands down the best in the mud.
Todd