After two years of trying to rehabilitate my crazy Corella Jack, I finally decided enough was enough. I've been trying to get him handleable. It seems it's just not destined to be. He loves the company of people and all the attention, but he just does not like being handled (or is that he just loves the reaction he gets from biting).
I sent him to Nursery that has avaries all around it. Jack was placed at the head avaries by the entrance. He will continue to get all the attention he desires, but will no longer get the opportunity to bite the hand that feeds him... :)
PS. I got another corella, this time a hand raised baby named Louie and he's doing great so far.