I had someone offer the company where I work a .com domain which was a misspelling of our company's name. He concocted a site and a company name and what must have been a fake last name for himself, all based around the misspelled domain. Each time he wrote to us his offering price kept coming down, but was still in the tens of thousands. We said thanks, but no thanks....
Agreed that misspellings could be worthwhile traffic-wise, though. goofle.com or gooble.com might be good ones (if they were available, which they're not).