I could see this being mass-market in the $40-75 range for an embeded CPU to do the translation not counting the wii controllers.
I don't see how patents would be a problem. You still have to buy an official Nintendo controller to use it... I don't recall noticing any license that you could only use the remote on a wii...
If a game developer wanted to support this, it could be as an option. Thank of the PR boost they would get for being the "first" to allow a wiimote as an option. Obviously they wouldn't want to risk on making it a requirement...
Looks like it was working fairly well for Halo 2. The question is does it work better than the standard controller or not?








