Just a few things to clarify my position/thoughts on it.
I'm not adding any plugins to the forums. It's not needed, and only causes more time and effort every time I want to upgrade the forums to the latest version. I prefer to keep them as simple as possible, so that I don't have to go updating various things, or ending up with forums which lose features every time they get updated.
You do not need this in the forums. Really, you don't. You're just asking for it because it's the place you frequently visit, you assume that everyone should visit it, and should be the most logical place. Everyone uses the forum, right?
No!
People should be able to get the game, read all about it without having to go to the forums. They shouldn't have to read 20 sticky threads which haven't been updated for months because the users of the forum believe that's where the content should go, even though once a thread gets stickied the creator of the thread rarely updates the content of it.
Excuse that mini-rant.
What you probably want is just a page somewhere you can go and look at so you don't have to load the game. It can be hosted anywhere, just so that you've got a bookmark you can click so you can see the list of servers, and who is playing on each server. This makes it ideal as a small project for someone else, as they could make a mini site to provide the functionality for the small number of users this really matters to.
A couple of bits of advice to anyone who wants to do it...
As I've said before, the game query protocol is standard Torque (check T3D
here). Reading this should help describe the protocol. There's a few implementations of Torque compatible master servers available online as well for reference.
Please cache any data you get. The master server doesn't need querying every time your page loads, and the game servers don't need querying constantly either. A 60 second cache of any data your page gets from game servers should be reasonable.