ID:2222027
 
(See the best response by Nadrew.)
Is there a way to beat the 16 million turf limit?

Are dwarf fortress scale worlds possible in a multiplayer environment on Byond, presuming up to 200 maps will be loaded at any one time, with each 'square' being a map?

http://www.unlok.ca/assets/ world_map-region2-1050-10081-halfsize.png

If each map were 250x250, Byond would only be able to load 256 maps (approximately).

Presuming there are 256 players, each standing on a separate map, would this mean the maximum maps I can load is limited to this quantity?
Best response
You'd need to devise a means of loading and unloading the maps are they're needed. None of these games are actually loading those maps at the same time, they instance them out and only utilize them when they're needed.

You can only have around 30,000 z-layers in a world, even if each one is a single tile. I'm not sure of the exact number but it's pretty easy to figure out with a few lines of code. That number drops as the amount of turfs within each level increases.

Most of the time you'll hit your limits at around 1000x1000x10
In addition to what Nadrew said, this library may be of use:

http://www.byond.com/developer/IainPeregrine/dmm_suite

What you'd want to do is save the map when all of the players have left it, then load it again when someone enters.
Could I circumvent this issue with two Byond servers on the same machine, transferring between each of them as necessary?
That's a definite possibility if you have the resources to handle it.