Materials selection (bibliographer as it used to be known) is primarily an MLIS position in academic libraries, but it's a dying specialty now. I don't know any full-time bibliographers anymore. Academic libraries I worked in started doing away with those positions over 20 years ago. What's still done in-house tends to be parceled out among the reference librarians.
Big public systems tend to outsource their selections process now, especially in kiddie lit. The jobs are there, but not in libraries; those are vendor jobs, and they are mostly nowhere near NYC. Library jobbers like to work in cheaper markets: Brodart is in Williamsport, PA; Baker & Taylor is in now in Charlotte; and Ingram is in La Vergne, TN. (All of them have some positions open right now, BTW. I don't know any vendors who absolutely REQUIRE the MLS. They tend to find it useful, but don't require it.)
Bowker has a marketing opening right now. They are in New Providence, NJ -- still a bit too far to commute, but not completely out of the area.
(Bowker are the folks who bring you ISBN's, among other things.)
If you go to
www.librariansyellowpages.com, you can find all of the vendors based in a certain state. Open an advanced search, put a period in the keyword field and then choose your state.