After DeArmonds were discontinued, Fender sold Squire branded M series guitars.
Keep an eye out for a used Squire case.
I wouldn't say these are easy to find. I happened to luck onto one for cheap.
Perfect fit, flat lid, nicely made.
The only thing "wrong" with it was that it had a rather LARGE, gold Squire logo on it. :wink:
My Bluesbird case had a modest little Guild shield, not much bigger than a silver dollar. :?
A case from an Epi Alley Kat or Ibanez Artist models might work. Google the specs and compare dimensions.