In December, ABC will air a half-hour holiday special spun off from the "Shrek" movies - 'Shrek The Halls'. Shrek, Fiona, Donkey, Puss In Boots, and probably the second-tier of the cast (like Pinocchio, Gingerbread Man, and the Three Blind Mice) will star. And as far as those top four characters, all of the original actors will be involved. (That would mean Mike Meyers, Cameron Diaz, Eddie Murphy, and Antonio Banderas, respectively.)
Donkey has already appeared in the Tooniverse, thanks to his appearance on 'Pride Of The Family', which aired on NBC. There are also a few appearances in commercials for various products from computers to fast food chains. So it's likely that of all the cast of characters, Donkey will be first to get inducted into the TV Crossover Hall of Fame.