I remember I had a temporary stereo in one of my trucks once, and left the antenna laying up on the dash. It seemed to work fine. So I would guess you could hide it just about anywhere. You may not get great reception from weaker signals, but unless you're running way up north, or out west where stations are few and far between, it'll probably work out OK.
Does anyone make antenna's that would stick to the windshield like GM cars used to use? I know their's was between the glass, but if it was just stuck to the inside of the glass, wouldn't that work too?
Merle