Do you know of any dual degree programs between US and Spanish schools. I know that NYU has a dual degree MBA program with HEC in France, I was wondering if there are any such programs with schools in Spain.

Have you thought about the IEDE and the IESE MBA?

IEDE has an International MBA in Madrid-Shanghai-California (University of California - Irvine).

IESE has some modules in the US.

The Spanish schools have built up quite a solid reputation, especially IESE (see Economist ranking!)... And Spain is always a good place to spend a year or two ;-)