You have a great idea here. - Game purchase, maybe some cosmetic micro transactions - Studio - Kickstarter (I'd chip in) I don't know what you'd build it on. The realism and pure size of the Arma 2 engine is what's makes this so awesome, but it's frankly absolute shit bug/gameplay wise in many aspects. It just doesn't work. Like ever. I'd suggest at least developing your own netcode as I can hardly never get in to servers, nor my friends.