While we're getting ready to host our own event, here are some other events of similar groups or that are simply inspiring:
Sotahuuto is a yearly Finnish event that seems to have compatible rules. In 2016, it will be held in Ruovesi July 22nd to 24th, and is expected to draw over 600 participants. Here's a few videos that give an impression of their fighting: http://youtu.be/xpF87ajjtbE, http://youtu.be/OJkQHTYT_sU, and http://youtu.be/XFYPhmbXvpM
Kaltenberger Ritterturnier is the world's largest jousting tournament, held at a castle/brewery belonging to the Prince of Bavaria. While not Belegarth style, it's a nice experience.