What we have here is a Jeff Davis Designs original.

Built to fit in the rear cargo area of an air-cooled VW Bug.
Cut to hold 2 - 6"x9" speakers and 1-10" sub(you may be able to trim to sub hole to hold a 12").
I was able to mount my amp underneath the box.
Built from 3/4" MDF. Mostly carpeted. I had to trim some of the carpet off the sides to fit in my Bug as the car had a fresh carpet kit and was being stubborn. Where I removed the carpet, I painted black.
Measures 37 1/2" W, 13 1/4" deep, 9 3/4" H in front, 14" H in rear.
If you want, I will throw in the 8 gauge fuse holder and power wire(for an amp) I used in my Bug; already cut to length :)

$100
Matt (503)747-3562