Well a buddy of mine needed a new sub box for his truck, so we started brainstorming a while ago. It's a 99 tacoma extended cab. There's a hump where the rear seats fold down, and it has a compartment in there for the jack. He still wanted access to it, so we'd have to build around it. The sub he has to use is a Hertz Hi-energy 12" that we picked up for DIRT cheap. So I figured that we'd make a box that kind of rounded around the whole thing.. I guess pictures speak a thousand words..
Near the bottom part of it, we were going to make more enclosure go down, but there was a lot more room in there than I tohught, so we just laid a second piece down beside where the woofer mounts and sealed her up. There's also a brace in there to make it a little more rigid. It will also be seeing carpet in the near future.