You might try this web site :
When we were trying to make reservations my nephew was in college or just out. Now he has three kids, with the oldest just starting preschool this year. It may be a while before he is ready to try it again. As for myself, it has been a long time since I did any serious hiking and am not sure if I could get back in that kind of shape.
Thanks for filling in the details and sharing your experiences of hiking the Canyon.
nacl