I was thinking, (Dangerous, I know) that you could "Ballpark" the end of the LP hard pipe to where you want the grill, then use quick connects and flex tube to continue to the grill. Might even have them in its own little box w/ door so you would only have to open the "Grill Gas Door" to hook up... I guess it would be the opposite of the Diesel/Gas Door... If theres enough room inside the door, you can store the hose if its not permanently attached to the grill.
Or just mount the grill on a pullout drawer with several Pneumatic cylinders at the corners so it pops up to using height... then you only have to have a long enough flex cord.
(See why my thinking is dangerous? I get ideas...