the maps have to be a certain size or the client gets a little upset about it
so the only "little" map is tokuno - and that does not leave much room for dungeons then
the fel/tram maps in ML have a big unused area now to the east where you can build and freeze at if you want (or use muleditor and edit the map peice by peice in there) - otherwise you have to make the dungeons, land, water and everything else also
www.orbsydia.ca is working on a new project for map making -- and there old one is no longer available for download
ryndor also has a map maker also (i think i spelled it right)
but making a map is not as easy as people believe, it is actualy a very time consuming thing to do
and even once the map is down, you have to modify regions.xml, public moongates and a lot of other files
but orb's info on the new and old project is up there to read about the stuff you have to do, so you can start preparing for what you need (bitmaps, planning it all out, etc)