DCB,
You do realize that they used a motorcycle/4-wheeler engine/transmission. There is no way that you could get a 250cc turbo motorcycle engine to last for 100,000 miles. Sure, you could put the volt on a diet. Get rid of the heavy stuff, sound deadening, auto trans, put in lightweight race type seats :
CorSport Online Store: Racing & Safety - Racing Seats & Rails - 070.91.UU11
As well as get rid of most creature comforts, like a/c, gps, spare tire (how may people can even replace one themselves), power steering, power brakes, etc.
I am sure that if you got rid of everything that isnt necessary for the vehicle to go down the road, it would be much lighter (think 600 lbs lighter). But, and this is the problem, they are hoping to sell it to people and not just run a what if scenario for the low percentage of people out there that might be you (I cant remember if you have sworn the volt off).
All and all, the edison is a neat vehicle, but its premise is theoretical. I would like to see you try to live with a four passenger, 800lb, 40hp vehicle that needs a rebuild before 25k miles comes up. This rebuild would cover a piston for sure, and would most likely necessitate the adjustment of valves every 10k miles. Is this the best design?, well its damn good for the rules they had to meet. Is it something that is viable for the road? No, not quite. How would you like to buy a brand new vehicle with a 60 day warranty?