No, COCyclist, that's very much in the box, circa 1957. Back in The Day, endurance racers used rigid tonneaus and wrap-around windshield for the driver and a...thingie I can't name behind the driver's head (I've heard "head fairing" but that sounds a bit modern).
Here's a youtube video of a Lotus 11 set up thusly:
http://www.youtube.com/watch?NR=1&fe...&v=ODMqDhnwUDw
However a hardtop version (I know the Geo you mean--it was blue and had sort of a basket handle on the passenger side of the car) would be pretty original, all right. I'll have to scout up that Metro for pix of how he did the windshield. Any clues?