Hello Sfretts,
I think this is what you're after...It's called Extend A Flow by Marshall Brass part #535-00.Cost was $38.66 back in October of 2000.Purchased from an rv supply house.It comes with an adapter to go on your esixting lp tank which the 12 foot extender hose connects to which connects to your gas grill.All fittings included.
I took it a step further on our SOB trailer and ran the hose on the inside of the trailer frame through groumets to a junction box with an LP approved cut off valve.I made up an additional 12 foot LP gas approved hose with LP gas approved brass quick disconnects to reach the grill wherever I decided to put it.
Uesd the setup trouble free for 8+ years and pulled it off just before selling the SOB trailer.I will be installing it on the Mountaineer soon.