First and foremost, the collaborator that comes to my mind would be Tim Burton. I think his dark sense of whimsy would very much appeal to Hitchcock. I feel the two have much in common and would enjoy each others company as well as input. it is said that much of Burton's story lines are autobiographical- and haven't we seen Hitchcock in all of his own films?
and as long as we we're talking Tim Burton, we must of course include the composer Danny Elfman. I think Hitchcock would approve his attention to detail, the way his compositions fill in the story line by taking you through a journey all their own, then bring you right back on point. Hitchcock would also have appreciated the use of a full symphonic orchestra combined with the latest electronic sound equipment as well.
to round out this collaboration, we must add Burton's costume designer Colleen Atwood who among other things, has noticed that shoulders are peculiar to peregrines.