Nano-based Ultracapacitors Focus of US-Spanish Collaboration:

Link (http://www.evworld.com/news.cfm?newsid=18757)

Caps are coming, and will be added to battery packs to take full advantage of regenerative braking.

Assuming of course that EEStor will not come from the left field and blow away the other ultracapacitors, including this one, and the automotive Li ion batteries. Seems to be a lot of activity on this blog site (but not much news):
http://bariumtitanate.blogspot.com/