OK, my two cents:
There are some programs that have reputations that may imply you'll get a better chance at some sort of fellowship. That being said, I think you could talk to just about anyone and find someone who got a fellowship somewhere that reflected well on the program. That does not necessarily translate to YOU getting into one. I know two people who got fellowships in EMS with the FDNY, I would suppose that's a 'top notch' fellowship to those who would like to do EMS. That being said, both of those guys were residents at NY Methodist in Brooklyn, NY. I don't think either of them went to Methodist in search of that fellowship, they kind of fell into a place where it worked well for the first guy, who may have had some pull with the second.
Those may be the kind of things the original poster is looking for, but those stories are hard to come by because there's really no place to post all those kinds of things for each residency. Therefor, it becomes more something you learn kind of 'willy nilly' from forums like this, or if you actually interview somewhere and they tell you this fact.
I find most people in EM tend to want to see lots of different stuff, trauma, cardiac cases, wierd stuff that you'll be the star for recognizing later as an attending, etc. and I think you get that stuff just about anywhere because EM is just that wierd to begin with, I mean, where do these f_ _ _ _ _ _ people come from anyway? If you want to have a big name under your belt, that's fine, but I would say you can become famous (if that's your need) by working hard and finding a way to do research that moves along the specialty. If that's the case you really only need to read the literature, find out who's doing the research you're interested in, and contact them. You don't even have to be in their program, they'll be glad to have you interested in their work and will help you out. Sometimes the best way to get noticed is to break new ground in a place no one's really looking at. It's all about the work, I think. The work is crazy, busy, hectic, full of nonsense, and full of fun. If you're the EM type you'll love it anywhere you are.