McMaster-Carr has an air powered conveyor with all the components but the straight pipe, which is just PVC pipe you can get from your local supplier. Go to www.mcmaster.com and look up air-powered conveyor.
Also, I know of a company that might sell you a used version of this system. I purchased one for my former employer, and it was used less than 3 months. They have the components sitting in storage, and may be willing to part with it for a song. Send me a message at paul.vanderkley@lennoxind.com if you want to give this route a try.