Ask HN: Your wish list for a site map generator app

Before anybody gives me a rap on the knuckle, I'll clarify our position directly:

Like most (if not all), we're aware of the fact that there are many (good) site map generators already available out there.

The reason why we wish to 'roll our own' is two-fold:

1) As a training exercise for some of our interns and

2) We rather like building things from scratch and in the process, usually create something with at least some unique features

...and this brings me back to the subject of my thread:

What features would folks here like to have in a web-based site map generator app?

Thanks in advance for all suggestions.