[dsraven]

youngrodder, your filler is capped under the floor with an access door to the filler, correct? like a fuel fill door on the side of the vehicle on newer cars? that way the cap could vent or overflow a bit when filling but the fumes/gas would escape outside the cab? some bed floor fillers I have seen are like that and some are a filler tube coming through the floor with a simple cap at the bed floor level. some guys use a marine fuel tank filler as they are usually chromed or are finished nicely. they usually have a little chain or something inside the filler tube to keep the cap from getting lost as well. some also have the extra tube for the fill vent. some are flat with a special key to open, some are locking, some have a flip up lever to twist it open. they would look equally nice on a fender mount, an under floor mount or in the bed floor if thats what you are after. some marine places also sell the aesthetically pleasing access doors as well.