UMass-Amherst has to be up there. Off the top of my head from when I was there we had people marching Crown, Cadets, Madison, Blue Stars, Spartans, Citations, Surf, Teal Sound and 7th Regiment, along Bucs on the DCA side. Probably a couple more that I forgot about too.
Plus on staff we have/had Mike Klesch, Colin McNutt, Thom Hannum, GNP (RIP), etc.