[_ck_]

If rewriting a PM plugin I would try to use as much internal stuff that bbPress has as possible. For example use the same hooks actions/filters that the new post form uses (and specify post id #0), which would make it work with many plugins. And run the message through pre_text before saving and then output through post_text when displaying.

It’s also technically possible to do the whole thing inside of one single file for easy maintenance and make it part of the profile tabs. Look at bb-reputation to see the trick to making profile tabs within a single file, it requires a “wrapper”.