I once ordered rigid clear plastic tubing & end caps from a packaging catalog. (pre-internet!) These came in 6' lengths of various sizes. Caps in bags of 100. You cut what you need & with 2 end caps you have a custom length container. HOWEVER, I cannot remember the company & have searched all over the internet to no avail. If anybody finds a company selling these things, please be so kind as to post it. I will be eternally grateful.