Wow I had a lot of reading to catch up on!
The asteroids in SM are NOT cookies. But I did hear something else cool--I'm sure there's someone around here who can confirm. A CM told me once that if you look at the barcodes on the walls along the last part of the queue (where the line splits into 2 "halves") from just the right angle, they become letters that spell out the names of Imagineers that worked on the attraction. I have never tried it myself though.
The other two surplus sellers I can think of are Surplus Kingdom and Sell and Ship; they are also on eBay. I have some really neat stuff from both of them.
Umm....ok, here are some more that no one has mentioned.
--In Spaceship Earth, in the new scene with the garage/PC inventor, there are at least 2 new Hidden Mickeys that I saw myself yesterday. One is on the window of the car, immediately on your left, and the other is on the wall of the garage, also on your left, above the AA.
--In Journey Into Imagination, there are four homages to the original attraction. The most obvious is right after the "intro" portion with the video screens, as your cars come around the corner there is a door right in front of you labeled "Dean Finder." The second is in the big room towards the end with all the Figments singing "One Little Spark"--on the sheet music in the center of the room, there is a silhouette of the Dream Catcher machine. And in the last scene just before unload (the one with the big Eric Idle moon) the Figment AA standing on the planet was used in the original attraction. It was located in the "theatrical" scene where Figment was sitting at his makeup mirror surrounded by costume trunks, and was located on the right side of the ride track. Today he has a new paint job, of course. And, in Figment's house, in the living room, the video that plays on the TV has Dreamfinder in it. You can only see him if you happen to be riding by at JUST the right moment--but he is there; I have seen him!!!
--Walt Disney has two windows dedicated to him along Main Street in the MK. One is above the train station, facing out towards the entrance plaza, listing him as "Walter E. Disney, Chief Engineer." The second is above the ice-cream parlor, facing the Hub. The story behind that one, I heard, is that his brother Roy wanted it there so his brother could always look out and see his Castle.
--Expedition Everest is constructed in three separate parts. The ride track, the Yeti, and the mountain are all separately engineered systems that do not touch each other at any point.
--The American Adventure pavilion in Epcot uses the opposite of forced perspective: The building is actually about 5 stories tall, but is made to look much smaller to preserve the vista across the lake and not make it appear larger than its neighbors. The windows, instead of getting smaller as you go up, actually get larger, and the large hedges planted against the walls where the building meets the ground are placed there to help hide the fact that the building is so big.