I can think of a few uses for the extra 1 grand you are paying for that Titan Z.... ah yes, building an entire platform to hold even more vanilla Titans, making the price premium of the Titan Z seem bogus.
So with 6 grand I can buy either 2 Titan Zs and stare at them while I still save more bucks for the platform to actually use them, or get 5 titans and a platform with x5 PCI-E.
Btw, was it an open design? Didnt look like a blower to me. If it isnt a blower, i dont see the point of making this product as you are really hurting the thermal design of your rack with all those Titan Z's throwing the heat into the case.