It has been about 6 months now and I thought I would throw and update on this thread. We are weeks away from full production. The last of our little girls will be to size and ready to go into the rotation.
http://img845.imageshack.us/img845/8863/bothracks.jpg
We have had no issues with chewing. I don't think they can even get their teeth onto the ridges in the bottoms of the tubs. I am really liking these bus tubs. They are solid, and as long as no one is chewing them, I think they will last for a very long time.
We have found several people that want to buy our rats. Two people in particular have bigger snakes. We are going to need more grow out tubs, so I started looking around and found these big mixing tubs. 36"x24"x8"
http://img34.imageshack.us/img34/9572/tubbytub.jpg
I'm considering making a 4 tub grow out rack with these big boys so I have more room to grow out some larges and extra larges for the interested buyers. It might be a month or more before I get around to building this thing, but when I do, I'll put up some more pictures.