I just traded for one of these from a guy who just upgraded to a Grip. He had used it for about a year and it is still in great shape. I don't think he ever built a frame for the inside, but I knew I wanted to.
Since I like to work with materials I have on hand (I'm a thrifty "Joe Disc-Golfer"...mentioned in an earlier post), I cut & assembled a pegboard box/frame and snugged it into the bottom pocket. However, I only like to carry about 16 discs or less (including putters), so I put my drivers and mids in the top pocket and my putters in the bottom front. The putters fit better there during play than they do in the top. But you can only zip one of them in. The other can go into the bottom compartment after play.
The bottom compartment has serious storage potential. Plus, I really like that it sits upright and I don't have to bend to the ground to pull a driver or mid. Putters, well...
I'm thinking of bolting thick wooden dowels or lengths of pvc to the underside of the bag (similar to the Grip's plastic runners).