i need help with a sub box for an 02 ex cab

i have an 02 ex cab silverado and i want to put 4 10's under my rear seat that fire forward, i have 2 jl audio 12w3's right now but i want more bass, anyhow if you know of a place or a person that could build me such a box, let meknow cause id like to have one built, also if you have pics of your setup, post them here so i could see, thanks

Im curious as to why you want to go to 10's instead of 12's?? True that more speakers equals more volume, but why not add another 12? You can always build your own box to accomodate your 10's. It's not hard at all, it just takes patience and time. BTW.. heres a pic of my current setup. It's a bad pic, but will do for now.

http://files.automotiveforums.com/gallery/watermark.php?file=/500/93396system_while-med.jpg

I saw this one silverado in Truckin' Mag that had 4 10's in it. The custom box had them Pointing forward in like a "W" shape. So they were pointing eachother a little bit. I think they also had to raise the rear seat a few inches to make everything fit. If i can fint tha article online ill post it.