Mordenmail, you could use screws in the chassis connected to a spade. The best ground you would probably have is your wall plug ground. You could connect the final wire to the ground plug on a male ac plug. Neither the hot or the neutral should have any connection to them.
I suspect that you would have to lift the ac grounds of all of your ac cords or you would introduce a third path to ground and worse hum. I have never tried this solution.
I suspect that you would have to lift the ac grounds of all of your ac cords or you would introduce a third path to ground and worse hum. I have never tried this solution.