Speaking of Food Network Star, Michele Ragussis once competed on Chopped.
Michael Gilletto is one odd case. As The Other Wiki notes, he appears on Restaurant: Impossible as one of the four chefs to become the head chef. He initially wins, but it was clear he was having second thoughts and did not take the job after all. Later, when Food Network aired a short home-cooked version (aptly named "The Chopped Open Your Basket Challenge'', essentially a promo advertisement), he's one of the judges.
What Could Have Been: Ted Allen humorously remarked that Chopped was going to take place in an eccentric millionaire's mansion with the losing dish in each round going to the chihuahua. It was too much for Food Network.