Shillelagh and other spellcasting stats

So there are several ways to get the Shillelagh spell, many of which allow you to select the stat you use to cast it.  Many are straight forward, the feat lets you pick it when you select it now, you can pick it up through a Warlock pact, bards and their spell stealing ways.  So I come to Barbarian or Pugilist.  Both have subclasses where CON is their spellcasting stat.  Can you use Shillelagh with CON?

It seems unlikely in WotC material, but if you're including third-party classes and subclasses, then probably.

(You could always just homebrew such a subclass yourself, after all, though it may not work on DDB.)