Thanks for all of the posts, guys. I'm no longer actively developing this add-on, and am looking forward to someone picking it up from me.
If you are interested in maintaining and coding the add-on, please private message me, so that we can get something worked out.
@Jogib I'm missing the knowledge required to make dynamic menus within XenForo (the kind that allow you to add extra servers and whatnot), but from a standpoint of my code that powers the add-on, it would be fairly quick/easy.
@Xyphien you can also make a custom template edit to the template messages to include a CSS class along the lines of "group_GroupName" to apply special styling for groups which aren't staff. Best of luck!
I'm currently working on a style which has a feature that allows posts by the current visitor to have the post information moved to the right - and I decided that maybe this feature will look better if the post information is also coloured similarly to already existing messaging applications...
I suppose if you or one of your friends was/is really comfortable with xF, or just looking for adventure, you could edit the email templates... Although I'm sure they might get overwritten when you update, it's a thought, if this is very, very important to you.
@Sadik B While I can't say I'm a very serious freelancer, I do think that this is something people would be interested in.
However I'm not sure how much people would be willing to drop on such a product, there are quite a few pages out there around the net describing freelancing on elance and...