Pickup Truck Topper for TTT Roof

I've seen a few mentions of using a pickup truck topper as the roof for a TTT but the only actual build I've found is the one: http://www.tnttt.com/viewtopic.php?f=50&t=45827
Is anyone aware of any others?
Any thoughts, pro or con?
Is anyone aware of any others?
Any thoughts, pro or con?