yes, the Ciocc uses 135mm rear spacing, which isn't unheard of in modern tandems. The new Ritchey BreakAway tandem also uses 135mm rear spacing.

If you invest in the right rim & spokes & hub, the difference in strength or durability between a 135mm and a 145mm rear hub is practically insignificant. Remember, up front all bikes, including heavily loaded tandems, still rely on a 100mm wide hub.

If your tandem team needs more strength than the latest burly set of 29er hoops you can order a 135mm rear hub with steel axle from the usual component makers.