A lot of people make them. I'm pretty sure that Pun made some and I know for sure that WWA made some.
PBNation: A land of AGG Twib's trying to express their ability to pwn, genocidal idiots advocating their bloody ideals, extremists of every persuasion, and flamers stoking the coals.
Look for a WWA tube used. Usually ~$40. And completely ugly in my opinion. I had one of Mongo's one piece feeds like in the link above and I really like the styling of it. And Airsoldier products (ASP) has raw Punisher's one piece feeds in stock right now.