Mostly we just have people posting their individual meet ups. Unlike with the brony fandom, pony collector meets tend to not be quite as plentiful.
If a meet is coming up and has a group of collectors organising it, you tend to find they will have a pretty active thread which is never further from the top of the Corral than page 3 or 4; and I think individual meet threads are helpful to organisers to let them have group discussions.
A general thread is possible and did exist in the past but I dont really think there are enough live meets at one time to keep it active.