I figure that many collectors could sell off some of their unused computers to pay for one of these. That's what I would do, knowing now how great these things are.I'd love to own one, but the odds of one ever being in my price range are as likely as Apple producing a standard midtower Mac desktop anytime soon.
It's a nice looking machine though, that much is certain. It'd fit my desire for a PCI Power Mac quite well. Not to mention it wouldn't take up much desk space, which is an issue for me these days, and is likely to remain an issue for some time to come.
Being vertical, they don't take much space at all, and the keyboard slides under the computer. I have the base unit behind the TAM, and the TAM on a corner, but you can easily have the base unit on the floor too.
I have paired a black USB mouse (taken from a PM Director's Edition) with my TAM, because the trackpad can get a little old. I find it great for general use, but if I am copying files everywhere, and need a lot of control, the mouse is superior.
PS - Nowhere have I found that these can handle OS X, even with the Sonnet upgrade. You can apparently brick your TAM, and some have been brought back from the brink, but if you really need OS X, use something else!