From Think Progress, here's a suggestion by Mitt Romney that the Constitution be amended to require that future presidents all have at least three years of business experience, a rule that would have excluded Dwight D. Eisenhower and John McCain, among others, from eligibility.
The last president we had with an MBA as well as a considerable business background was George W. Bush. Funny how Romney does not mention how well that worked out.
It's also funny that in this video Romney mentions a constitutional requirement having to do with the birthplace of the president. The Constitution contains no such provision, requiring only that the president be a "natural born citizen" of the United States. Did Romney forget that his own father, who ran for president in 1968, and who considered himself constitutionally qualified for that office, was born in Mexico? George Romney nevertheless regarded himself as a natural born U.S. citizen.
UPDATE: Timothy Egan in the New York Times explains in more detail why requiring that the president have a business background is a terrible idea.