All three would be good choices. There are a lot of parts and equipment available for all of them. I would personally go with a toyota, they are small,dependable,and very tough. Just look at Ivan Stewarts Truck.
For lots of pics of cool prerunners, check out the Inland Prerunners website at http://prerunners.com . Also, for some good info on building true prerunners, you may want to subscribe to the prerunner mailing list sponsored by off-road.com . Try www.prerunner.com to see if that gets you to the mailing list. If that doesn't work, go to the race section of off-road.com to sign up for the mailing list.