I do not know if they are still made. I would think that older gun smith shops may have one in inventory. Guns where I live do not bring as much money. I have one and I don't realy know why they or criteria where put on. Or realy how to adjust it.
I have a old Western Auto/Revalation 16ga bolt action with a polly choke. I know alot of people use rimfire for squirells but I use this gun. Ive had several people tell me to cut that off and install screw in's. But I like the ability for the quick change of patter, just reach up and twist.
As far as still making them, Ive not seen any on NIB guns. But I have seen screw in choke tubes that is a polly choke diffrent thread fitting for diffrent guns same twisting setting as the old ones.
yes the poly choke is still made... cabelas sells them too, and the company that makes them sells them too, there are a few different versions, screw in and non screw in and with and without a muzzel break, the non screw in ones youll have to send the barrel into the company. more info can be found at http://www.poly-choke.com