Like you I don’t know much beyond this LARP beyond its trailer and this announcement text (taken from an entry in the Google+ LARP Community.
Spectaculum Technologiae Et Artis Mundi (S.T.E.A.M.)
Is an upcoming steampunk larp which pits teams representing various nations and political entities against each other in political, artistic, scientific and athletic arenas as they vie for prestige and the admiration of the world. Steam and gear machines, top athletes, influential merchants and the foremost thinkers – all will be at the Great Exhibition.
August 2014, Latvia.
More details will be revealed as they are decided upon.