Yes, they exist (e.g., http://www.panasonic.co.uk/html/en_G...895/index.html
) - but you can't buy them in North America for two main reasons:
1. The manufacturers don't want the legal hassles of trying to sell a video recorder in the U.S.. Even though they put in all the restrictions demanded to prevent recording of copyrighted material, they're concerned that they could be hit with a frivolous lawsuit by some organization like the MPAA that would cost them millions to defend.
2. Most people who want an HD video recorder in the U.S. rent one cheap from their cable/satellite company. There isn't a big enough market of people who want to own one to make it worthwhile to take a chance on the legal costs.