im not sure the exact number, but i believe ed barker has upwards of 2 german bow students right now. maybe a bu student will chime with the exact number and some hard facts about the other teachers there.
dont sleep on the l.a schools. if youve got what it takes, colburn is unbelievable. usc is also a great school with 3 -- 4 if you count john clayton, which you totally should -- fantastic teachers (who, unlike teachers at other big schools, get along). and the program there is still developing, but chris hanulik at ucla is unquestionably on par with any player i have ever heard -- definitely the best german bow. and of course check out indiana, but im sure that goes without saying.
the best advice i can give to someone picking a teacher is to try and find the person who will help bring out what you want your musical voice to be. this is easier said than done, and requires knowing a lot about yourself (what you can, cant, and want to do), in addition to the teachers youre considering. compatibility is key, both in musical and personal terms. unfortunately, the many great music schools in the country (and elsewhere) are incredibly spread out, but i suggest you try and get acquainted with as many teachers as possible (i know it seems like my answer to everything, but try and get the the isb convention this summer).
with that said, you probably dont want to pick a school solely because of the teacher. im a freshman at iu, and although lessons, rep class, and masterclass are always very rewarding, i think the majority of what i have learned this semester has come outside of all that, whether it be from listening to professional recordings, hearing/watching/talking to other players, recording myself, experimenting in the practice room, or even recalling things from before college. just keep in mind that only a handful of the 168 hours in a week are spent in your teachers presence.