Will 383 pistons work in a 426 Wedge ?

You have discovered the major problem with a 413/426W......piston availability. Even 383 stock replacements tend to have slightly too much compression for modern gas, and the forged selection is getting pretty thin for a 383 too.
But I tend to agree... if your gonna spend custom piston money for a 426W, might as well stroke it to boot.
But to tell the truth, I think I would use a 3.91, or 4.15 stroke, and just pay the piper for a custom piston.
($1000 for a cast piston is criminal, imo). BBC con rods in assorted lengths might make coming up with a workable combo easier.
You do know that a GOOD 426W block can probably go .070..... to standard 440 bore size. (that's only .005 of material removed more than a .060 piston.