There's a couple of issues:
1) It's almost October and you want to do a rotation by January. Most of the residencies have already filled their schedules with rotating medical students, and there may not be room at highly desirable programs for another student who's asking for the elective this late. You may end up getting the student rotations that are "left over" out of, well, not having anyone ask to rotate there. But that might turn out okay -- those are also the programs most likely to have a positive history of hiring FMG residents.
2) Any student, regardless of whether they are an AMG or FMG, can rotate at any program in the country at programs ranging from top-tier to on-probation, if they ask for the rotation EARLY enough. The question for you is, "If I rotate at this program, will they consider me as a residency applicant despite my being a FMG?" You don't want to waste your time rotating at a residency that wouldn't consider your application; yet there are a few relatively well respected residencies that have FMG residents (who weren't already, say, the most well-respected academic anesthesiologist in their country of origin prior to coming to residency).
Email or call each residency you're interested in and ask whether they have room for you to rotate. If they offer you an elective, then maybe the next thing to investigate is whether they have a history of considering FMG's seriously for their residency spots. If they have a strong history of being anti-FMG in resident selection, don't bother with the elective even if they offer it unless you really need a letter of recommendation.
Also, if you are interested in specific geographic regions, perhaps you could post asking about those specifically and some of us could respond if we've seen these programs already.... There ARE actually a lot of programs that interview FMG's even in some pretty competitive cities.