There was a Disneyland special in 1990 that talked about future plans. They mentioned Indiana Jones (1991), The muppets show (1991), The Little Mermaid (1993), Alien Encounter (1994), Dick Tracy Show (1996), Baby Hermon's ride in what would become ToonTown, and Hollywoodland.
It's interesting to see how all of these things played out or played into what would be a new park, but damn - I wish we could have gotten Alien Encounter.... :-/
Here is the video: YouTube - The Disneyland Story (5/5)
And here is the first video of the five incase you wanted to watch the whole thing (pretty awesome): YouTube - The Disneyland Story (1/5)
On a side note - if anyone knows of anymore videos online like this please reply and add some links! Thanks!