I wouldn't recommend it: the name and logo are trademarked, and even if you replaced those, if anyone noticed the rest of the copying, you'd be the laughingstock of the internet. Who'd want to buy your product then?
Google copying Yahoo's front page code? Okay, that'll be in the news and everyone will have a good laugh.
Some Joe Schmoe Web Developer lifting CSS/HTML from an unknown client to sell to an unknown client? Eh, not so much. This probably happens often and goes undetected.