Gap and Texas Brigade are the big makers of the M40A1 through M40A5. They take up most of the stocks other then the Military. You might be able to find a used on but its going to be real hard. It might be easyer to just get in line and have the whole thing made. It will only take a year to a year and a half. Good luck too you on this one, if you get one (I hope you do) Post some pics, we always need more gun porn.
Yeah, I don't mind waiting but I was wanting a return stock to build a replica on and it being a return stock and having the worn down Krylon, it would just be cool to have for its authenticity. My buddy has one and I wish that thing could talk. It was around during the the invasion of Iraq and Ramadi.