First off, great challenge! Hopefully there will be a lot of participants. Second, how "large" does a cold war have to be to be considered ok for the challenge? Does it have to be on a continental/ regional scale, or could it perhaps be a "feud"/war between two ruling houses in a city – where the battle-place or scene of buildup would be the streets and places of the city. A Montague v Capulet sort of thing perhaps?

Cheers,
Tainotim