I like the first of Jon and Amy's the best.

One suggestion; since Moab is mountains and desert, maybe make mountains on one side of the VX and a desert on the other (cacti, cow skull, stone arch?). Also, maybe use the Isuzu font? http://www.fontineed.com/font/isuzu

Either way, I'm all in and I think that it would look mighty fine on the back of a t-shirt across the shoulders or the front across the chest.

Way to go Jon and Amy with an M.