Peacebay Power Co, Ltd. http://www.peacebay.com/ "...the super high energy and reliable Ni-MH rechargeable battery manufacturer, that meets your every requirement for the battery power. Based in Tianjin China, Peacebay has provided the high quality products to many countries around the world. The world-class production facilities, strong technical support and intelligent people build Peacebay into one of the best-reputed Ni-MH rechargeable battery manufacturers in China. ... "

http://www.pwtcbattery.com/ - Power Technology Incorporated - The web site doesn't contain enough detail, but it discusses using lead but being lighter than conventional batteries. They have patents so those ought to be tracked down (see this page).

http://www.enersysreservepower.com/ - Makers of the Hawker batteries.

http://www.erun.ch/ - Makes a Lithium battery modules with built-in BMS and Kokam cells. They may be available for sale through the swiss scooter maker http://www.swissroller.ch/

a123systems.com has developed a Lithium ION battery cell. They claim 100C peak discharges and 5 minute recharges. Unfortunately their site is a little weak on details.