It's a very cool project for the technically savvy, but if you sell it to consumers, you'd have to provide support, something that could be time consuming. Or make it foolproof (Apple's strength).

I have a Raspbmc setup, and I get a fair amount of interest from visitors who are impressed, and want their own cheap media centers. I dissuade them, unless I am sure they can troubleshoot computer issues, SSH/SFTP, image an SD card, and know basic SQL.