Has anyone found a locking gas cap for their Trailblazer? I have a 2004 and none of the auto parts stores around here ( Autozone and NAPA ) have anything that fits. Siphoning is on the increase in my neck of the woods.

http://www.stant.com/part_locator/index.cfm?go=stant_part_locator
and then go to amazon.com, search for "stant gas cap" and order the right part number