Opening of Ray Bradbury Presents
I'm not sure of this really counts as a hidden Mickey, but it's wonderful none the less. When growing up I used to enjoy Ray Bradbury Theater on HBO. There was a huge less than hidden Mickey (and a picture of Walt and Lilly) in the opening. An entire wall of the studio is devoted to a huge Mickey when he switches on the lights. You can find the opening on Youtube.
It's wonderful that Ray gave such a large tribute to his old friend and mutual amdierer. From what i hear Ray had an effect on the parks but I don't know the ins and outs of it.