Are there any WWII military gliders either available or in the works for MSFS? An Airspeed Horsa or Waco CG-4 perhaps? Virtavia’s recently released Short Stirling MkIV would be a good fit for towing these troop & materiel carriers.
Guess I’ll take that as a “No”. 
It’s something I used to ask for when using DCS World and IL-2 
Would be nice to have, alhough they’re, as you say, “gliders”, not “sailplanes”