Some comments.

"For long term maintainability it would probably be good to eventually replace the hard-coded html generated with a hard-coded template."

I agree with this. The main power of Roundup for me is its flexibility. These hard-coded stuffs should be more easily editable somehow, like an extension. (OK, we can do this.)

"(and implementing the checklist or radiolist display methods in addition to menu)"

I also agree with this. The .menu() for multilinks is suitable for IT specialists only imho. But this is due to web standards, not to Roundup. :)