Actually, that would be a pretty cool idea! It would be like The World in the .hack series! It doesn't have to fit with the KH series' plot but it would probably be like a side story, ya know?
C'mon people! Just cause it sounds weird, doesn't mean you have to call it a stupid idea! You could create your own characters with their own weapons and basically put yourself in Traverse Town or Halloween Town or where ever! But if they made it more in the future, it could be a virtual reality game! Would that be cool or what? ^_^;;