http://h10088.www1.hp.com/cda/gap/display/main/index.jsp?zn=gap&cp=20000-13698-12989-27064-27065^312768_4041_100__
If you haven't seen it yet. This has every media that has been given to HP for testing. Not a complete list by far (you have to pay HP to get on the list), but every media that has been found by HP to run on their printers are listed here.