Hi gusbuf,
Subject to first confirming that any retailer or manufacturer on the list you wish to deal with is completely transparent (see this article) and to making sure that any mattress you are considering meets the quality/value guidelines here … the better options or possibilities I’m aware of in and around the Buffalo, NY area are listed in post #29 here.
Jamestown is the only local manufacturer I’m aware of in the area as well and I would certainly include them in your research although there is also a local retailer that I’ve just added to the list that sells a range of component mattresses that have custom layering options available and there are a few other local retailers that may be also worth considering.
Phoenix