Beast is not a multiboxing guild per se, it's just a regular guild that happens to accept multiboxers. It's also a guild that
spams low level zones in order to boost its ranks (I know because both my roommate and I were low level players on
KJ at one time and continually got Beast guild invites). I will say that the ginvite spam from Beast wasn't nearly as bad
as the ginvite spam from other guilds at that time.

Guilds that 'happen to accept multiboxers' are all over and they can't all have their own sub-forum to help advertise.
There are no set guidelines on what it takes to get a sub-forum here but, I would say you would need a dedicated
(and populated) multiboxing specific guild with multiboxing goals before it would be considered. There are currently
multiboxing guilds that are active and populated that don't even have their own sub-forum (probably because it's kinda
pointless and they have their own website).

Also, you can see the posts near the bottom of the first page on the Multiboxing Guild General Public forum date all
the way back to July. So, if you're worried that your guild invite to others is going to get knocked off of the first page
anytime soon... I wouldn't sweat it.