Neal: Good question, but I can't see it being that dramatically different - import system prices usually give us a good idea of what it'll cost in the US, even if the game prices aren't the same. And given the XBox Live Arcade, it would have to be in the same price range to compete.
Alisha: I may suck at explaining this, but... There's copyrights, then there's patents. Patents are on technology and inventions, while copyrights are for artistic (or 'artistic') creations. Unlike copyrights, patents only stay good for 20 years before it's out for everyone to use - as the NES came out 20 or so years ago, the technology, for the most part, is free for everyone to use.
Edit: John beat me to it, but he didn't explain the patent deal.
Edit 2: Wikipedia on NES clones!