I work for a company that makes implantable medical devices, and I recently went looking for a new plastic tubing supplier. I found these guys at a company named Precision Extrusion, Inc. and they make real high quality Medical Tubing (This links to their site). I was suprised that I hadn't heard of them before, but I guess they're a little smaller than their competition. Anyway, I've had a great experience with them because they really took the time to work with me to make the custom tubing that I really need.