I dont see why you couldn't get an offroad vehicle, or all terrain vehicle, type policy on it. You can insure a boat, along with all of your electronics and fishing gear under a watercraft policy; or at least that is the deal I have with my boat insure with USAA (which is then underwritten to progressive).
I currently have tags on my TJ, and just have regular car insurance on it and a stock of receipts for all of the aftermarket stuff on it in order to substantiate the additional cost.