Lokar has ed-5005 which is 13.5".
I am looking at pipe and tube fittings on Amazon supply. Maybe I can do a 5/8 straight thread o-ring adapted to either steel tube, brake line, or even high temp DOT nylon. Just gotta find a way to prevent leaks, make it swivel (if needed), and provide a clear path for dipstick to travel unimpeded.
I wonder if anything exists to adapt inverted flare (brake line) to 5/8 o-ring male.
What is the OD of a dipstick tube?