US Plastics [url=http://www.usplastic.com/catalog/search.asp?search=tenite&category=78:5c7c1]http://www.usplastic.com/catalog/search.asp?search=tenite&category=78[/url:5c7c1]
Has tenite tubes (clear plastic -rigid) in 1/4 inch incriments and I think they sell it by the foot. Thin walls -- various options 1/16 --1/32 inch ot so up to arround 2" dia and 1/8 inch thick in sizes there and up.
AgMD