Thanks 32. If we had an English wheel and planishing hammer, we could probably form the tunnel out of one or several pieces, but since we don't, this is the next best way as we see it. Dan did the same thing on the first body (that I inherited :D ) and it came out pretty well using this method. No one ever sees the underside of the tunnel anyway, so the skeleton showing isn't a problem, and it does add a lot of strength to it.
Brad, we actually did talk about those fasteners, but Dan is using button heads all over the car to fasten down stuff like the stake pockets, rear body section, etc, so he wanted to keep the theme going everywhere in the car. When they are painted body color they will look like rivets pretty much.
Just for comparison, here is the tunnel Dan built the same way in the first body. The main difference is that the first tunnel was much larger because that version was airbagged and was going to sit on the ground when laid out. So the engine had to be mounted a lot higher so the pan would not hit the ground. This new tunnel is much smaller as is the driveshaft tunnel.
Don