Is 'couple' ever used in the sense of 'some'?

Yes. It's used all the time to mean an undefined small quantity.

Come here, I want to ask you a couple of questions.

This is likely to be more than two questions.

I've had a couple of ideas I'd like to go over with you.

Translation: Get ready to be bored.

But if you use it regarding specific items, it probably means just two:

Can you bring me back a couple of Cokes from the machine?

But don't be surprised if the person replies:

Sure. How many do you want?

Couple originally referred to a pairing (as in two things that go together) and later developed into simply meaning two but has since widened its meaning to a few or a handful.