Owned both the 9mm and 380 versions. The 380 may be the better of the two with such a smooth slide action.OP, If you can find one, look at the Sig 290RS. Small, polymer, 380 or 9mm. Needs a trigger, but meets your criteria. Galloway used to have a trigger kit, but I think they infringed on someone. Maybe RS somebody. You're the one that said, "searching for something that doesn't exist" so while you're at it, 290's are out there but be sure to get the RS. Stands for Re-Strike
Good micro-compact but heavy. Really wish Sig would have refined this handgun to compliment the P365.