I am not positive about rentals around here, but if anyone can help, try www.sunrisetri.com. Ask for Frank. He has 2 stores, a tri specific store in Suffolk county (western suffolk) and a bike shop in Nassau county. Owner is a great guy, could probably help you out.
Another poster had success with this issue a while back by calling Brands, in Wantagh.
See here:
http://forum.slowtwitch.com/gforum.cgi?post=1236835;search_string=brands%20;#1236835