I got an idea that just might be good.
If you remember BLv0002 you had to pick up bricks to build. How about in the minigame you start with a brick count of 0, until you find scattered bricks through the map those will be used as resources for your buildings. If another player has a brick you want you can simply trade bricks with players.
If you find a brick on the ground it might have a brick count through 1-10 I guess, after you use them up you'll need to look for more.
You get what I mean?