So, I was perusing the MythTV mailing lists, when I came across a post which linked to this device (actually, it linked to the 1210, but the 1220 is better, IMHO):

DS-1220 SATA Enclosure

In short, for $800, you get a rack-mountable enclosure that will take up to 12 SATA drives and present them to a host PC. Which means I could turn that into a massive MythTV storage device! As a bonus, it comes with literally all the gear you need to get the thing working: all the drive mounts, cabling, an eSATA PCI card, screws… it’s a very complete package.

Unfortunately, I should probably actually, you know, finish our basement first before I start drooling over such things. And after that, I’d still want to buy a proper server rack. And a couple rackmount cases so I could rack up my firewall and Myth backend. And then there’s all the gear I want for my media room, such as an HD-capable projector, screen, gear for a myth frontend, some sort of audio system…