Mylar? I did do them on mylar and vellum before I graduated and got into an office with CAD. I started the project in 1986 or 87 doing an elevation of main street on mylar at 1/4" scale. (From the cup and saucer past the cinema to the hat shop, it was about 14" high and 5' long before I stopped) I still have a DLP and Epcot resorts on paper so I probably swithched around 1992 or so. I work on vectorworks. It works pretty well for 2d. and it cad do 3d but all the 3d stuff I want to make is crazy. I can't really take software for designing houses and make it do mountains of rockwork and rollercoasters with banked curves. I have a friend who's doing an amazing recreation of Disneyland in blender.
http://www.disneyland3d.blogspot.com/
He also has renderings on flickr (links from his blog)
I'm thinking of learning blender but haven't gotten around to it yet
I'm just doing it for fun and I like having a collection that's disney related but not commercial (Now someone from Consumer products is going to read this and start selling millions of them at the parks at outrageous prices like beenie babies or pin collecting) I like that I've developed a hobby that's cummulative. If I got into video games I would have a nice high score but I would have died a million times, and who really cares about high scores? But I just add a bit more each week and now I have an impressive collection.
Ed