ORIGINAL: gratechef
Why doesn't Dubro or someone come out with a fuel tank with a nipple on the back of the bottle for refueling/defueling access?
Because it's a really bad idea and totally unnecessary.
If you had a cowl, the line can come out the front of the tank and terminate on the wall of the cowl.
If you don't have a cowl, a fuel dot is not needed.
A tap at the rear or side of the tank is just begging to leak inside the plane.
As I said, Fuel dots are for cowled engines. You just want something that is not necessary - so you are having to jump through all kinds of hoops to get it.