Can't believe I havent seen this before now, but I know I want one.
http://www.bbc.co.uk/news/business-11301831(Ok its not directly C5 related so feel free to move to a more appropriate place)
The one to watch here is the T.27 - which is an all electric vehicle with a range of up to 100miles, top of speed of 90mph and 0-60 in under 15 seconds.
Costs quite a lot more than its oil burning brother, but definitely on my shopping list for 2012!