I have a convention I didn't see on the list either. I'm attending Gamescom in Cologne Germany next August because it happens to coincide with a trip I was taking.
I looked for it on the list, but didn't see it. http://www.gamescom-cologne.com/en/game ... /index.php
There's the website, and the convention takes place from August 17th-21st.
It's not an anime con- perhaps why it's not on the site you take your info from- but it's a gaming convention and gaming seems to play a major role in influencing cosplay even at anime cons... And I know they do cosplay there, so anime, game, whatever, it's still a huge convention that cosplayers will be at. Not sure if you'll decide to add it, but figured I'd put that out there.