Thanks all for your responses. I'm glad to read that at least a few think the idea has some merit. The idea just came to me today, so I haven't thought through any details such as funding, location (although NYC would probably be best), and who would run it. Lack of general interest would also be a problem -- interest in WTS/JWs would be limited to a niche audience, to say the least.
An electronic library with a complete listing of WTS publications would, of course, reach far more people than a physical library. I've gathered from past posts that a web site that featured extensive reproductions of WT literature has recently been shut down because the WTS claimed copyright infringement. I don't know if similar restrictions would apply to WT literature in a physical library open to the public.
I'm in no position myself to pursue this idea, as I must maintain my anonymity for now (lack of funds and rural location are also obstacles). Nor am I knowledgeable about WTS history and old publications. Some here have made extensive studies, and compared to them I know virtually nothing. I just decided to throw the idea out there and see if anyone thinks it worth picking up the ball and running with it.