I'll help you out. I was looking for the same thing. There is no easy solution. I'm very good at modifications and I found it to difficult to do what I wanted to do. I was looking at cutting the plastic in the back by the 3rd row and putting a sub behind it, but it would have been to much work.
There is no "commander" specific box. My friend has his set up so the amp is screwed to one of the seats, and there's a very small box that goes between the lift gate and the rear seat. Honestly though, you cannot get alot of power out of that small of space, and its kinda of cheap looking. I wanted to keep my 3rd row, but decided that my audio while driving is worth more than carrying passangers or cargo. However, it would only take me 10 minutes to pull them out if I needed to.