I did see a canopy once in the field, I believe it was an Arty carrier (M113) and the driver had a Plexiglas canopy that clamped down over the hatch. We were all gob-smacked when we saw it! Didn't get any pics nor have I seen one since but I swear it was real.... Sort of a helicopter bubble with a flat windshield at the front complete with windshield wiper.. We were all bundled up (I was driving my TOW carrier) and the guy driving the canopy carrier wasn't even wearing a jacket, just his regular combats, beret and head set... under glass of course.. ;-)