I\'m totally understanding the documentation on expanding the Comments app in Django, and really would like to stick with the automatic functionality but...
My quick and dirty solution: I made the the 'email' and 'url' fields hidden fields, with an arbitrary value to get rid of 'this field is required' errors.
It's not elegant, but it's quick and I didn't have to subclass CommentForm. All the work of adding comments was done in the template, which is nice. It looks like this (warning: not tested, since it's a simplified version of my actual code):
{% get_comment_form for entry as form %}