+9 Aura IIRC
Hermetic architecture, in cobination with Verditius magi, alchemists, and astrologers. One magus cold represent all four.
They don't all get along, they share not a single vision, and only House Tremere seeks to rule the world.
Why bother? Most hermetic magi (the exception being those few newly gauntleted ones who don't count anyways in any decision making 
) already have access to pretty much anything they might want from the mundane world, short of power perse*. Has the idea of taking over (as in becoming the absolute god-king) of the ants in that anthill in your garden ever struck your fancy? No? Well, that's probably how most magi feel about ruling the mundane world.