Just got myself 8 AAs (Rechargeable) from IKEA for my custom 9,6 V battery pack which I use for my Nikko Super Cruiser. A bit overkill when you count the capacity lol. :
Nikko 6.0v Ni-Cd battery cassette
Make your own RC Car Battery Pack or Repair NIKKO Ni-Cd 6.0V-620mAh - YouTube