Aha! All is clear now.
Except for poly.verts, of course. There is definitely a verts method defined for any CP::Shape::Poly; last on the list of poly.methods.sort.
I'm not thinking in terms of large projects, heh; I'm just feeling my way around. But it might be useful to have those methods even in large projects, for debugging. In most game engines, you can toggle the rendering of things like the collision bounding boxes/shapes/convex hulls, for debugging purposes.
Thanks a lot for those extensions -- I'd already added a couple of similar properties to the Space object (my own active_shapes, etc) that basically just hangs onto the data we pass to chipmunk, but after seeing the poly.verts method, I thought I might have been way off. As with a lot of this stuff, when you're learning a new thing, you don't know how much you're missing because you're going about it the wrong way, and how much you're missing because you're just looking in the wrong place.
Thanks a ton for this (and, of course, Chipmunk) I will try this out when I get home from work.