Very nice yak, I'm working in a Jackson Bigtuna for my son and I. I have a Gobi rack, not cheap, but very versatile and can easily hold two yaks plus lots of gear plus two Mt. Bikes.
If you really want to go custom, there are lots of good custom guys in town. I would check out the trucks gone wild forums, most of the really good fab guys are building mud trucks. I'm sure there is one close to you. What part of town are you in, love to hook up and do some yakin. I have a friend that has a cabin near Alexander Springs and was thinking of putting together a Kayak/wheelin trip when it cools off a little.