I actually thought about that once, taking one of my 2T's and building a mobile siren station out of it on a trailer of some sorts, kinda like the Thunderbolt 7000 series. Since you brought this up, I may actually consider building it
All you would really need is a compatible 120/240VAC generator, a trailer, an extendable pole or something to mount the 2T on, then wire it up to a motor starter and an AR timer. And if you would want to park it somewhere just add a radio decoder to it and keep the encoder in your vehicle, nearby or on you - or you could just manually activate it.
That's a really good idea!