What I"d do is this:
Settle in with a jar of water, a roll of GS, a pile of Cadian torsos, High elf legs and unhelmeted heads and go from there.
Unlike other alternative heads/bodies, there is nothing for Fremen in the miniatures range in plastics. Making them is the hard work.
Alternatively, you could buy the Necromunda Van Saar gangers.
They look to be wearing stillsuits.
Still, that would cost you the earth. Depends on what your time is worth, really.
And how much you want an army that is "yours".
Hey! Where'd ... Everybody ... go?