I was going to make one a lot like that tbh....well, with more than 8W of load (wtf actually....what kind of switches are they using that are so weak?! must be something else in the design), so yeah, that would work very well.

EDIT: well, damn....that design sucks. Rather than switching from 12V/ground (12V operating voltage) to a 12V/5V (7V operating voltage) to a 12V/open (off) setup, they have a semi-pwm setup :-/ Guess I'm still making my own (that will have nearly as much load handling as my PSU can...just simple switches, no crazy circuitry).