Thanks, guys.
Whitey80, the Harbor Freight lift was something I looked at. But then I saw an industrial lift table come up on Ebay, and my mind started cranking away. The flat top meant I wouldn't have to put a cover over the hole if I submerged it. And for an old 911 (or VW Beetle), the flat top made it perfect for lifting the car and also functioning as good flooring when it's down and a decent work bench when it's up. Plus, I liked that it's American-made and built to a pretty durable standard -- these things aren't made for lifting cars, but they're built for a tougher hydraulic duty cycle and are structurally expected to take lateral hits from forklifts. And the fact that I got it really cheap because it was second-hand made it impossible to pass up. I paid $455 for it, and then did the installation myself.
Rickster71, it's funny that you mention Popular Mechanics. I have a pillar in the middle of the garage, which ended up being both a blessing and a curse. It led me to an old Popular Mechanics booklet that had a layout which worked for my situation.
And then in an unrelated development, Popular Mechanics contacted me a couple of years ago, and included me in their website edition and also in the August 2011 issue:
IMcloud, you're right about the fold-down bench not coming down when the car is in place. But I've got dozens of other C-clamps and Vise Grips stored in other parts of the shop. So far, it's worked all right. It's not the perfect shop for everyone. But given my budget and space restraints, I've been very happy with it.
Full disclosure for the audioholics crowd: it's got a pretty lousy (but loud) stereo. And it's rarely as clean in real life as it is in the pictures.