Just some thoughts on this massive project. I think it is a wonderful idea..but lets stop and think for a sec..
First off...
The Base....Will one person complete the entire base or will several people contribute as has been mentioned before..if several people are working on a base..lets think about a few things..exact measurements, and i mean exact, will have to be put into place if we hope to achieve any type of continuity. Ex..the exact thinkness of celluclay, grass to be placed here, water to go here, sand exactly hear...etc. Interlocking pieces would have to match spot on..
Next...
Say we have one person be the one to put the base together...this person would have to be responsible for a lot of things..ex. would have to recieve all shipments of figures, vehicles, etc..would have to have every piece of the puzzle before beginning any groundwork..as vehicles would be needed for tracks..if vehicles were coming out of water ..they would need to be put into place b4 water could be poured, footprints., etc.
This is just a few examples of some trouble spots that i see.
However, perhaps a series of small dioramas built be diffrent individuals, each diorama depicting a specific scene, that will be placed side by side with all the other dioramas to tell the overall story..
Just my two cents worth here..I'm in whatever way we decide to proceed with it..
Mary

(++)