there are some really cool "dream" idea's in the mod section by scottishalien I think his name was? but there are no offical new maps and there probably will never be

EDIT: there actually in the "ideas" section for example:

http://forums.demigodthegame.com/352531

Yeah - as it stands, the only realistic option is to modify tower and portal placement on existing maps... and its somewhat archaic as to how you have to do that (manually entering coordinates and then using trial and error to see if you have everything where you want it).  There are a few customized maps in the modding forums, so you can at the very least try out some small variations. 

I agree - but if you consider the other dota style games, they have like 1 or 2 maps at best.  It justs a bummer that we can't really create any new maps.