Excuse me if this comes thru twice, been having ::cough:: technical difficulties. This matter came up awhile back on some of the HP fan groups I belong to and it was mentioned that JKR herself does not own the rights to anything to do with the Harry Potter movies. She (or her publisher) sold them to Warner Films, so even if she wanted to, she can't permit use of movie characters. For that you need to go to Warner's licensing department. If they say yes, it's no doubt gonna cost a small fortune, depending on what particular rights you want. Non-profit fan usage might be allowed, with a whole bunch of restrictions, but if it's something you want to sell they'll either say no or demand a really big chunk of the pie. On the bright side, even if they refuse permission, they'll at least know there's a market for a product that's certainly gonna promote their movies.