This idea is one has a lot of future. I hope it works.
http://ca.autos.yahoo.com/p/1040/new-hybrid-shocker
In this article, they refer to the Bose suspension system, but there is no mention of energy return which could surely be implemented.
http://www.bose.com/controller?event=VIEW_STATIC_PAGE_EVENT&url=/learning/project_sound/suspension_challenge.jsp
http://auto.howstuffworks.com/car-suspension9.htm
Will it do better than Citroen's active suspension system ? You should see how good this is on a C6.
Luc