The concern we would have with those is they globally add snowball damage, which we don't want. It needs to be able to be reduced to a local size, say as a region flag.
The closest thing to being useful would be Snowballer, but it just assigns a permission node, and as far as I know you can't limit them by region unless you make a new layer a-la the PvP-off zone and apply it for Snowball-On. Am I right about this
Kainzo Sleaker ?
Also, players would need to supply their own snowballs/buy them from a DHX shop as there would be no automated arena system unless we coded it, which wouldn't be a high priority atm.