Something like that -might- work, at least in theory. I did some experimenting with it now but all I managed to do what to get the program to hang when I replaced the maps by simply overwriting the files. My guess it is not as easy as one would hope. (Even if you could miraculously get it to work I presume the custom maps would have to be built with the same version of Unity as the executable). But if someone has the time and patience, please look into this further, I would be interested to know.