Have you looked at the Ariel Atom?

Here's a link to a video from the show Top Gear (I'm sure you'll be impressed!):
http://www.youtube.com/watch?v=WaWoo82zNUA
I think they're awesome. Not particularly practical, but look like a real blast, none the less.
For the "purist", nothing beats this.

Here's a link to their web site:
http://www.arielmotor.co.uk/04/frames.htm

They're available in Canada now.