Most current info on forum here: http://laserhacker.com/forum/index.php?topic=18.0
 
Maxwell 2600 Farad 2.5V Ultracapacitor, capacitor power storage, used Qty 12 US $165.00
 
Possibly the best deal on these right now: http://www.ebay.com/itm/Maxwell
 
If my memory is correct I bought a bunch of these at $6.00 each about two years ago in a flash clearance sale from Electronics Goldmine.