Personally I'm not sure why this is interesting. Are you just reskinning the same content? Theme and setting can be nice for flavour, but it's the mechanics at the heart of the game that really matter.
Having said that, you should check out A Rogue's Dream: http://www.cutgar.net/?p=100 It's a 7DRL that didn't quite make it, but it had the cool idea (which works) of pulling themes in from the web. So you say your name is "cat" and it makes a cat icon for you from Google image search, chooses enemy types and player powers based on Google autocomplete for searches like "cats hate ..." It has infinite themes essentially, all built up from the sum of human knowledge on the internet. It's open source too if you want to give it a gander.
Wow Darren that's a great idea.
A person could provide just the basics of a game they'd like to play, and the 'game builder AI' would build it.
I would love for a company with vast resources to do something like that.