http://www.maxwell.com/news/release.asp?PRID=222 First thing first, I would say Their current top models (ultracapacitors) store about 5Wh per kg. If/when they manage to up that for a houndred times, Tesla's bat-pack would only weigh about 100kg (now it is 450kg).
I hope these companies with ultra-capacitators are thinking about using it in cars and other transport.
Hmm, EEStor's ultracaps are claimed have about 260Wh/kg. That is about 50 times more than current Maxwell's best ultracaps. I can only wish they are true.
Re: Maxwell Tech. is set to develope Ultracapacitor-Based Starter System For Car “Ultracapacitors store less energy than batteries, but can deliver ample current for starting at temperatures as low as -40 degrees, so a system combining batteries and ultracapacitors provides a superior solution.” From the Maxwell article.