Cavalry Arms used to make a unique polymer AR-15 lower receiver until they were shutdown by the BATFE for failing to comply with some regulations. The current owner of the molds used to produce the lowers is putting them, along with all the associated IP, up for sale. He sale price is about $60,000. The buyer will need a press and nylon welding machine before production could start. These cost about $90,000.
I really liked the CAV-15 lowers with their integrated pistol grips and A2-style stocks. I hope someone purchases the mold and starts up production.
[ Many thanks to jdun1911 for emailing me the link. ]