My hunch is that if Glock is going to bother building a .380 stateside, it will be something in the LCP/P3AT mold.
I would love it if Glock produced a single stack anything. In the mold of the XDs, M&P Shield, or even Sig P238 (or 239), or really, anything small and concealable. It's my understanding though that Gaston Glock isn't interested in making guns specifically for civilians, and all of his designs are for Military and LE. This makes a small single stack anything from Glock a very low possibility...at least as long as Gaston is running the company.