I dont know of any LFS that have them in stock but I will say the ones I ordered off of reeftopia.com were excellent.
Im not sure if you are aware of this but some species of Nerite love to crawl out of your tank. Reeftopia claims they sell the ones that dont and I have to agree. Mine are usually in the rockwork and are excellent eaters.
Identifying between the two nerites is nearly impossible. Reefkeeping magazine did an article that covered them.