Arid and Pale by Michael Bacon is an example of a way to write Interactive Poetry in Inform… though I guess he says it’s not meant to be appreciated as poetry. Pale Blue Light by Kazuki Mishima (Dominic Delabruere) has sections of interactive poetry in that style interspersed with more traditional parser gameplay.
Harry Giles’s Ghost Highland Way is an interactive Twine poem, in the Scots language.
There’s also this hypertext piece that I’ve seen on the web, like from the old days of hypertext, that you might not want because it’s about the author’s memories of her romantic and erotic experiences though I don’t remember how graphic it is–ugh, I can’t remember what it is and it’s driving me up the wall. Anyone have any idea? I think it might have a number in its title, like Love-Memory One or something like that?
(All this said, I’d start with Carolyn’s suggestion of Renga in Four Parts.)
sub-Q actually has a few interactive poetry things. What Fuwa Bansaku Found is written with a semi-poetic structure, but Christmas Greetings, New Year’s Day, and A Man in His Life are all traditional poems that’ve had interactive elements added to them. I’d say that A Man in His Life is the most successful adaptation of these three.
There’s also The War of the Willows from IFComp. I know it got last place, but I think a lot of that was due to the awkward Python format. It has good writing.
I remembered the hypertext thing I was thinking of; it’s l0ve0ne by Judy Malloy. (I was much closer to the name than I thought!) Looking around a little it doesn’t seem that graphic… but I didn’t read every passage.