here's 2 good posts from page 7 and he is getting a new bed.
also, he was using a topper made for the earlier tacoma.
I can pretty much say from reading this and looking at the pictures that the shell is responsible for cracking the bed. The shell needs to be wider than what it is to support more of the weight 700+ lbs. Since the shell appears to be sitting on the inner quadrant of the rail it will exert outward pressure on the right and left bed rails which in turn will move (flex) outward. This flexing is exxagerated with off road conditions, hence the crack. If you think that a new bed will survive this same scenario you will be disappointed.
I would consider selling the topper and come up with one that is more adapted to this width. Otherwise you will end up with a major headache!
Everyone is blaming the SMC, Toyota, and the kitchen sink for this problem. The picture is getting clearer to me as to what caused this SMC bed to crack. The owner installed a cap/canopy/shell (whatever you may call it) that is about twice the weight of the Snugtop. He installed the cap by loading the bolts that run through the top of the composite material, and not the structural members of the truck. Then he flexed the SMC by bouncing this load up and down over some very rugged terrain. No wonder it ripped from the top as the pictures show.