I've been thinking of this for a while now,you know the Multi-tools?
Well,I was thinking that you could make something like that only it works a bit like the duplicator by selecting whole buildings at once.
Example:You set the setting on the Selector to Wrench Mode and you hit a building,then the standerd GUI for wrench pops up,you select fire under emmiters and hit ok,then the whole building would be on fire.
(Would need some restrictions on non-admins obviously)