Somebody please pack this all together and sell it for $50. This is how Apple do business. Sell hardware and software together.
Dell is supposedly going to be the first one on the scene with a real brand-named "mini-PC" device.
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.
What i learned from my previous media center (a Boxee, so basically a commercial XBMC fork): To stream FullHD over Wifi use NFS, not SMB, it is a difference. Atleast in my setup movies wouldn't play without buffering every few seconds over SMB.
Edit: also, from my experience openelec seems to be a little bit faster. Maybe because it's not booting the whole Debian userspace but only a minimal Linux.
Also: You can overclock your rPi without losing warranty (within limits). I overclocked mine to the maximum (700MHz -> 1000MHz) and it's still running without any cooling! :)