Okay, I took a pic of the frame.
The measurements are:
12" high (7.25" to the cross bar on the sides from the bottom, 4.75" more to the top)
10.5" across the front and back
8" deep
I used 1.5" PVC pipe for the bottom base, but 1" PVC pipe for the rest. This was important because with a thinner bottom, the discs would pop up when it was set down, and I think I had one actually pop out and roll away once. There's only one bar on the top, which keeps the top compartment supported. And the 45 degree elbows on the top-front (as opposed to the 90 degree elbow on the top-back) helped it fit better. If you want any other tips, let me know. This works really well for me in a bag that doesn't show hardly any wear after moderate usage for 1.5 years.
I do wish they had included some way to fit a water hydration bladder and a fold-out waterproof rain cover. Maybe on version 2.0. Also, my dream bag would have solar panels built-in (and again, protected from water), with a couple of USB ports to recharge phone, ipod, camera, GPS, etc. For now I've got a small one that holds about the same charge as an iphone.
Cheers,
Jeterdawg