Ok, turns out there is ONE modern rental in Tucson at the Barrio Metalicohttp://www.vrbo.com/146327
However, it is booked through September, and you have to rent a week at a time.
We're going to take a chance and stay at a non-modern, but to quote the phrase 'architecturally unique' property - Anna's Bottle House - out by the AZ Sonora Desert Museum. It's kind of in the middle of nowhere, but we couldn't resist...looks sort of Soleri-esquehttp://members.aol.com/raggtya/index.htm
For every complex question there is a simple answer, and it is wrong.