cool, my car is in the lead
here's another one, the extensively greenpeace ecomodded twingo... but this is a one box design, with virtually no break between the window and the hood... on the speedster i think the windshield is much more bubble shaped, so a great portion of the air goes round the sides... this curve may make it difficult to install normal wipers.
what i do notice is that on modern cars the A pillars sometimes extend before the window, especially at the base... now this could be to trap rain, but on some cars it looks a bit much... perhaps this is to contain a high pressure bubble to shield the wipers, feed the air intake for cabin cooling etc, but in a controlled manner so the bubble becomes part of the cars "ideal" aero profile
the benefit of a single wiper will greatly depend on the size and pressure of the bubble and what goes on at the sides near the A pillars