Surg,
I would disagree with you on one point.
Although I agree getting an MBA from a top 15 business school is essential if you plan on leaving medicine completely and switching careers to full-time consulting, investment banking, non-health care administration, etc, I don't agree that that holds true to those who will continue on as practicing clinicians.
As a practicing clinician who may be involved with leadership, administration, policy, consulting, entrepreneurship, etc. on the side, simply the fact that you have an MBA rather than where it's from is enough. They care much more about what you've done, rather than where you've gone to school. I doubt there is much of a different in the skills you are taught at different "ranked" business schools, and perhaps the most important part of an MD/MBA is simply learning to see things from the business perspective. The advantages of a top-ranked business school for an MD/MBA are probably mostly networking, which really just applies if you plan on being involved more with non-medical business opportunities.
I had the opportunity to go to the top-ranked business schools or to Rutgers Business School, which is a solid program but certainly not in the same league as Harvard, Wharton, Fuqua, etc. Sure, if all things were equal, I would have gone to the top b-school. But, they usually aren't, and definitely weren't in my case. Rutgers let me double up on courses to get the degree in one year (rather than two), offered a full scholarship (compared to ~ $70,000 in tuition at a top school), and allowed me to continue living near the important people in my life and do maintain close ties with the medical school (rather than uprooting myself to go to a top school).
So, if you want to continue as a practicing clinician (perhaps only part-time), I'd go with whatever situation makes the most sense for you, and wouldn't let the business school's reputation have much of an impact in your decision.
If you plan on using the MBA to switch careers, then you definitely need to go to a top business school, as you simply will not be recruited for many of the top business jobs graduating from a middle-tier business school.