The thing is, I'm realizing it's a standard that most books don't aspire to, including professional ones. This isn't to say that they're doing bad jobs (some are, but most aren't), but rather that I'm obsessing over things like harmonious size between the text block and the overall page. Without getting any geekier than that statement reveals, what I mean is: evenly-spaced margins, like a half an inch on all sides, are boring. Designs which create vertically symmetric spreads (a "spread" being both left and right pages considered together, with the join point being the axis) but asymmetric pages look, well, better. If you get the ratios right--as much art as science--and the combination of that design with the number of lines on the page and the length of the lines, given the typeface size and leading you've chosen, the page also becomes easier to read.
The problem is that most good book designs like that end up with somewhat "luxurious" margins. This is out of fashion, because it's perceived as wasting paper. Of course, you'll see a lot of trade paperbacks compensate for that by having big print, 12-point instead of 10, and wide leading between lines--the typographer wants to get close to the traditional optimal number of letters/words per line. If your line is mandated to have quarter-inch margins, you end up trying to reach the optimal by making the type bigger.
At any rate, the upshot of all this is that I realize the design I'm fiddling with is one that--well--it doesn't waste space, because the white space is part of the design. But it's easy to perceive it as wasteful. Its outside and bottom margins are twice that of the inside and top, 1″ and ½″ respectively. You can find nonfiction books with "proper" margins like that pretty easily--but you can't find novels set that way too often, at least not paperbacks.
I'm playing around with a less "luxurious" margin setup, and have one that I don't... hate. It doesn't have the same look, though; it's a little more crowded, although still readable. (And it'll still be perceived as a little wasteful, I suspect.)
This is, of course, the downside to those books on good typography I've been reading...