I've never seen them for sale before. I have, however, seen a couple given away on the NANFA forum. Just ask around, and maybe someone could get one for you if you pay for shipping, or send them a fish in return.
NYC? There are decent locations on Staten Island. Try the Clove Lake Park area. There's a trio of lakes there: Clove Lake, Martling's Pond, and another that I never knew the name of.
i have my larger rockbass with 5 LMB from 8 - 14in and i had the smaller one with a albino chanell cat for quite a while. shoot me a PM if your intersted