Your design looks great, except that I think most rear axles on TTTTs are rigidly fixed to the frame, they don't articulate. Well, thats how mine works and a lot of others that ive seen. However, if you do plan on making it articulate, use springs to keep the frame and body level. If you mount the rear axle rigid to the frame, you won't need the u joints. It makes it so much simpler for your first truck.After you make your first, then I think you would want to go on to bigger things.
