When looking at the rankings, keep in mind the methodology. U.S. News (2016) specialty rankings are based on input from business school deans and directors. Bloomberg (2012) has rankings based on student/alumni perception, as does Financial Times (2012). Note, as you may have found by now, Thunderbird no longer offers an MBA, but instead a Masters.
Also look into the following networks:
Partnership in International Management
https://www.pimnetwork.orgCenters for International Business Education and Research
https://ciberweb.msu.eduGlobal Business School Network
https://www.gbsnonline.orgGlobal Network for Advanced Management
https://advancedmanagement.netNearly every major business school has IB/GM focused courses, a course (often combined with a consulting project) which includes a week abroad, and a semester long exchange. This is great because no matter where you go you'll have options, but it makes differentiating them more difficult. If you have a particularly country you want to work in or with after graduation look at schools that have short or long term study abroad/projects in that country. A schools few also offer specializations/certificates, but even if it's not offered you can create your schedule so it mimics these types of programs.
One aspect to look at is whether there is an international requirement. At USC, for example, all FT MBA students are required to participate in PRIME. Booth has a specialized International MBA that also requires time abroad. As one AdCom member told me, their school has a lot of great but underutilized opportunities. I think if you are looking for a school that is strong in IB/GM then some preference should be given to those that make a global mentality part of the requirements.
Good luck in your search and if you need more help you can send me a PM.