Got an email from Midway today... 2nd chance Black Friday sale.
In the "MidwayUsa Products" they have a drag bag case listed 56" for 64.99$... Guessing under 100$ shipped (I got a pile of other stuff so can't guess it's solo shipping).
From the measurements, it should easily fit the AR50 with the stock removed. It has enough pouches and internal dividers that the stock should be able to ride safely away from your rifle.
My hard case is too large for taking to the range when my buddy drives, so I've been looking for a soft case option. Hopefully this will do the trick. If not, I have a case for a couple other bolt guns.