"While Domino has templates, it doesn't (AFAIK) have any way of scaffolding apps like this?"
It's called DXL, and it's been around since 2001. I have an entire web-based Domino business built around around doing *exactly* this type of thing on a much larger, far more complex scale. Literally millions of web forms with thousands of custom fields, validation, hidewhens, skip logic, etc.
"Without scaffolding then it would probably take the best part of a morning to hand-write all the code for this!"
Sounds like you answered the title of your post with this realization.