The Colorado, Canyon, and I-Series are still small pickups.
And the reason why these trucks are moving up in size has much to do with the shrinking market for small pickups...at any price. Just because it's cheap doesn't mean there's a market for it. For $11k, you can get an excellent used small pickup (I even priced a new Isuzu I-Series for $11,800) or a very good used full-sized pickup. Why would someone forego the added utility (and that is what these buyers want) for the "newness" of a truck from an untested brand name?