Earlier today I saw the crossover between Billy and Mandy and Kids Next Door. During the end credits they showed parodies of other cartoon crossovers. Included on the list was Samurai Mac. With Mac dressed as Samurai Jack and Bloo as Aku.
(Edit): My friend found a pic of the Samurai Mac spoof on photobucket.
http://i66.photobucket.com/albums/h2...SamuraiMac.jpg