Formerly, I could only choose between corridors going left and right at 90-degree angles; a certain amount of fixed hackery was used to jam each new corridor segment in at the end of the old one. So with a certain amount of quiet determination, I worked out the geometry required and made it so that a corridor can hie off at an arbitrary angle (90 degrees or less; I'm not interested in supporting oblong angles). The above map is set so that once a left or right curve is chosen, the corridor will continue at that angle and direction. It's also possible to randomize those settings completely, like so:
...for a much more jumbly and organic feel. I suppose it's not huge in the grand scheme of things, but I'm pretty pleased at getting this to work.
I would probably have gotten a lot more done over this long holiday weekend if a co-worker hadn't gotten me hooked on Champions Online. Damn you, co-worker! Damn yoooooooooou!