It was in a weekend newspaper entertainment liftout here in Sydney, sorry bro
Edit: Although, I think he may have mentioned it a little in the recent First Class issue of Empire, although not in as much detail. If i had a scanner i'd post it, because it's a great interview. It's by a film buff, so there are a lot of great questions about the failing of the franchise with X3 and Wolverine. Singer defends X3 but is very quiet about Wolverine lol. I'm sure if Donner wasn't there he may have had more to say :P