Returning extra fields with generatetreelist

I don't know if I'm going the right way with the tree behavior but I'm trying to build a comment system for a blog. I would like to have an indentation of 5 level depth.

The generatetreelist method looks like it would be the fastest way to accomplish this but it doesn't look like you can add fields to the query. Am I right ? Is there a way to modify the method ?

Thanks