See original thread on my pet barrier here...
http://www.vehicross.info/forums/showthread.php?t=15358
So one of the problems with this set-up is that you either carry the dog in the back, or cargo in the back, but not both. So when Grant put his Tone cargo box up for sale a few weeks ago, it gave me the idea you see below. I drilled two holes in the box for the barrier's support posts (measuring was a @#$%! as the top of the barrier only has a 1/2" margin for error to fit on the ceiling liner), added a cross-support on the left side of the box (don't think you can see it in the pictures though) to increase stability under my dog's weight, and added one of Dub's now famous LED light bars to illuminate the inside of the box at night. Originally the interior of the box was unfinished wood, so I also rattle-canned it black to match the exterior.
The structure is very solid - the box can't go anywhere because the bottom of the barrier is pressing down on it, and the barrier can't shift back and forth because it's now attached to the box. The only thing I would change would be to cut out a section in the middle of the barrier so I can reach the rear seat release easier. But that will require careful consideration of where to cut without weakening the wall too much. Probably something I'll fiddle with this weekend.
I'll have to take another picture of all the stuff I have crammed in the box already: Fix-A-Flat, WD-40 (step bar rattle), Silicone Lubricant (window lubricant), quart of oil, air compressor for tires, tow strap, California car duster for interior and exterior, first aid kit...