Kristin,
Quickly, because I'm running out the door. The "nonce" term is not as widely used as some may think... I'd never heard it until I joined this site.
One of the things I find unseemly in that 'book of forms' is that the author shies away from accepting a form until more than one person uses it. Seems disingenuous, although perhaps pragmatic for his ends.
From a research standpoint, I think I'd change my search terms. I'd look for 'innovative' forms, or look for people who've developed their own forms. Berryman comes to mind. I always giggle when people quote Frost and say "I want to make every poem sound different." Tell that to Berryman, who wrote 385 poems in a single form, one he'd invented, and which (as far as I know) no-one else ever used. Is that a 'nonce' form? Does he make it into that book? I have to admit I don't know, because I threw it across the room when I got to that definition...
Someone mentioned Meredith, which was an excellent hint. And there are lots of people who have invented their own forms, and then run with them, exploring what it let them do. If you look for those people, you may end up with a pretty interesting 'nonce' paper. I, for one, would love to read it!
Best,
Bill