I figured it out! after leafing through The Principles of Knitting again. Boy am I going to miss that doorstop when it goes back to the library.
If you want to knit in the round on straight needles, what you need are double-pointed needles. (which begs the question - why not just knit in the round on that set of dpns? and suggests the answer: because you've mislaid all but three of them.)
Cast on as many stitches as you need for the full round - for the purposes of this discussion, we'll say that's 20 stitches. Then - unless you want a sealed edge at the bottom, in which case get straight on to working one stitch and slipping the next with the yarn held in front - slip the first 10 stitches, as if to purl, onto a separate dpn. Now fold the work so that the two needles and all their stitches are parallel to each other.
Work the first stitch from the near needle onto a third dpn, and then, with the yarn held in front, slip the first stitch from the back needle onto a third dpn as if to purl it. Work the next stitch from the near needle and again, with yarn in front, slip the next stitch from the back needle onto the third dpn. Keep going until all the stitches are on the third dpn and then turn the work.
Now it's time to work what will prove to be the other half of your first row, by working the stitches that were slipped before and slipping the ones that were worked already. Just as on the first side, you're holding the yarn in front for every slipped stitch.
I know this sounds labour-intensive and also like you'd need a cable needle to do any decreasing later (since you couldn't just K2tog but would have to get the slipped stitch in between out of the way), but I liked it. My experiment was with ribbing and what I ended up with was K, bring yarn to front, slip, P, slip, put yarn in back to knit and then back to the front to slip, P, slip, etc. Very soothing and, once you can see the pocket that's forming, intriguing. Next time I'd go for all Purl slip Purl slip so I wouldn't have to waggle the yarn around, and then flip the work inside out when I was done. Or not, if I was knitting something I wanted to be smooth on the inside.
Tomorrow I'm going to a knitting fest with vendors and if any of them are selling small-size dps, look out! I need everything below 2.75mm. And then maybe I'll try a mitten in the round on straight needles.