Ohio hunter here, and like you, wanted the LW long slide, to go with my 6" LW barrel. Two hunting seasons have come, and gone, and the long slides still aren't available. After giving it considerable thought, and coming to the realization of what a long slide is going to cost, I have decided to just stay with the regular G20 slide, and use the 6" barrel dropped in for hunting! 350-400 dollars is not worth spending, for me, just to add 1 1/2 inches of sighting plane to the G20.
Not sure if they still do, but heard, at one time, Caspian made a LS, but I'm sure they would be costly also.