Been looking in that one a lot along with the functions_forumlist. I must be too dense to find what I am looking for.
The construct_forum_bit looks like it builds the list and shells it out to the correct template (as far as where I know the html is parsed). However, there are no queries in there to note and I am getting a bit lost looking through it. Maybe just more time trying to understand each line of code will help.
The other area was the 'cache_ordered_forums', but that has no join (except the already filled tachyjoin), so if that was where I needed to spend my time I guess I would have to add my own joins in there too along with my own table fields.
Do you wanna be paid to do a quick example for me of what I want to do?