can a coat of paint be TOO thin?

If it's texture you're looking to achieve with this technique, use lacquer based paints and thin them out. Spray from a distance, you'll find the paint actually dries before it hits the model (don't worry it sticks) and leaves you with anything from a flat finish to what resembles fine sandpaper.

probably the only texture you could get is if you sprayed with the airbrush too far away or with too much pressure. The only texture I've ever got on a model was from that. Usually overly thin paint will just need a billion coats to cover but dry pretty much ok... It might build up in the detail and obscure some of it too.

Testors makes a carpeting material (like extremely fine fuzz) you can put a layer of spray adhesive on the part you wanna carpet, then either coat or sift the carpet material over it. I saw it at Hobby Lobby the other day.