I was talking to a buddy the other day that is a bit of an antenna nut. He's the guy that sits for fun modeling stuff and thinking up antenna designs that he builds, plays with and then gets bored with and goes on to another design to be worked on.
So he had an idea that seemed genius as a hidden antenna.
Taking a small satellite dish, and tying the center conductor of the LNA to the metal of the dish body, then driving the feed cable of the dish mounted on the eave of a house at the ground with a matching network and laying radials in the ground. Effectively making the cable to the dish a radiator, and the dish becoming a capacitance hat.
We didn't go into alot of detail, but the basic premise is there and would seems to be a workable solution to a hidden antenna in plain site.
Of course, the dishes are covered under the whatever TV receiver law that allows them basically anywhere and it just looks like a standard satellite dish with a cable running down the side of a house connected to it.