I got the idea from Gnomoria, a game coming out soon. Basically, the idea is like a minecraft map, an unlimited forest, once you reach the end it expands more, but make sure it starts big as to not cause major lag every ten seconds. You can collect wood and minerals with RPG Tools and use them as blocks to build and govern a town. You can go to war with other towns, create alliances and what-not. It would be a hard thing to create, but it'd be worth it.
/discuss