I have seen them made of aluminized exhaust tubing as well as aluminum and pvc. Is that the source of your problem?
I built my own hard intake pipes for my turbo Supra project, using 2.5" aluminized tubing and 3" rubber hose connecting clamps from a hardware store.
[img width= height= alt=ImageBam image upload]http://thumbnails9.imagebam.com/2321/28dd9f23207970.gif[/img]
You should be able to do something similar, using some pre-bent 45's and 90's. A barbed air line connectors welded to the tube(or threaded into the PVC if you used it) should work for the two hoses that connect to the intake tube.
