My curiosity got the better of me, and I went looking for these "Mini-ITX" motherboards. I found them at VIA's mainboard site, and discovered that in addition to the 17cm×17cm Mini-ITX models, they've got a 12cm×12cm "Nano-ITX" board (pictured, right).
So now I'm thinking: for portable recording purposes, it would be awesome to have a tiny system that makes almost no noise (the low-power CPUs don't need fans, but there's not much I can do about the hard drive spinning). Add the smallest (and cheapest) flat-panel monitor possible (maybe even salvage a dead notebook computer's screen), move the Delta 1010LT into the tiny computer (which means it would have to be a Mini-ITX, as the Nano-ITX only has a mini-PCI slot), and bam!
Now only two questions remain: Where can one get one of these little marvels (since my usual sources don't carry them), and how much do they cost?
Answer: AxionTech, among others, and between $118 and $255 for various models with a 1GHz CPU installed. Not bad!