Thanks for the kind comments, Laundrew and BrystonFan:
It took awhile to design the cabinet, but we had a demanding situation with an open wall on the right side of the room. That's why you see a surround speaker mounted on the cabinet (behind which is a Cisco business-class network switch, a Brickwall surge protector for the switch and the DVR, and cable runs to the TV and the subwoofers on the front wall of the room: see photos below). There are smoked glass doors, which are off in this photo. The shelves are very strong and have about a ten-inch square hole in the center for convection cooling, with a whisper exhaust fan at the top of the cabinet; this seems to work quite well, as the gear is never more than warm after several hours of listening. On the wall at the back of the cabinet are two 20-amp dedicated circuits and the speaker cable runs to the 7.2 audio channels. Behind the three doors at the top are spaces with shelving for storage, and the bottom has ten deep drawers for DVDs and Blu-rays. There's a hidden drawer above the Oppo player, just below the center of the cabinet, for accessories.
You're right, placing the 6BSST at the top was tempting a hernia (it took two of us on eight-foot stepladders), and I'll likely rearrange the gear to place it lower. Alas, I didn't have enough length on the speaker cables to place the amp lower. I'll likely just put in Niles switchplates with five-way binding posts and run speaker cables to a more hernia-friendly location for the amps.
The shelves are adjustable vertically in fine increments, and each is mounted to 200-pound sliders that fully extend. It's a bit disconcerting when the 96-pound 6BSST is rolled all the way out, but access to cables isn't a problem, as there's plenty of room at the back of the two-foot deep shelves. When we have a rare power outage and I need to reset the power on the amps, out comes the stepladder; otherwise, the trusty SP3 handles power duties through its 12V triggers.
Oh, what we do in the service of music . . .
______________Sunny Napa Valley