Yay KH
There is 1, count it 1 t-shirt out there relating to Kingdom Hearts. Haha, it was sold at Hot Topic, and Hot Topic is owned by "Limited Too" funny, isn't it? Anyway, if you go to the Hot Topic website, they don't even sell it anymore. It was a t-shirt that had Jack Skellington, Sora, Donald, and Goofy in their Halloween Town costumes. The ONLY reason the t-shirt was made and sold at Hot Topic was because of Jack Skellington, which was depressing. Officially, in the US, there are no other T-Shirts and stuff for the series.
So Sad...
I know a lot of people anywhere between 10-20, even older, who enjoy the Kingdom Hearts Series, and are also fans of Disney. And those not fans of Disney when they play Kingdom Hearts, become Disney fans. The game was complete breakthrough. Final Fantasy VII has the most characters in the games, and it's one of the most popular games that Square-Enix has created. Disney is seriously missing out by not selling some kind of Kingdom Hearts Merchandise.
You see, the best thing about Kingdom Hearts is that it's SOOOOO diverse, you can sell it's merchandise ANYWHERE in the parks, especially in the Magic Kingdom. Thanks to Nightmare Before Christmas, Kingdom Hearts merchandise relating to Jack Skellington can be sold at The Haunted Mansion. Thanks to Pirates of the Caribbean, merchandise can be sold at that right. Thanks to Alice in Wonderland, merchandise can be sold in Fantasyland. Thanks to Mickey and Minnie and Donald and Goofy, items can be sold at Mickey's Toon Town Fair. Literally EVERY type of Disney Movie is in the game, and that's what makes it so diverse, and so different and out there. Sora, Donald, and Goofy's costumes are designed, in the game, in such a way that their colors fit in even in the realistic world of Pirates of the Caribbean. Now THAT is a successful collaboration.