Velomobiles.
Lovely things. Not without their drawbacks - they need a garage or decent shed to store them in, and they are a bit heavy up hill, And the cost, of course. But on the flat, or downhill, the aerodynamics are superb, and the sheer psychological benefit of getting out of the wind is huge. Those are the reasons they are big in Europe, especially the Low Countries, where hills are less of an issue and winds can be unremitting. I rode a Trice Borealis at the York Rally a couple of years back, in the year when several marquees took off, and as soon as I got in, the wind just vanished.
My favourite is probably the WAW - looks like the front cut off a Spitfire.
This year's Spezi show was absolutely dripping with them, including the Rotovelo from Oz, which might be the way to get the cost down, being made of kayak plastic - easy to mould, and more robust/less precious for everyday use than fibreglass.
http://www.trisled.com.au/rotovelo.asp
Sadly at the moment, the import cost means they aren't much cheaper in this country.