Success! Sort of...
I have managed to make an orb tool but the lights were so faint it almost wasn't worth bothering.
The circuit comprised of 8 2.2v led's connected to 2*9v batteries. I was pleased with the construction but the lights were so damn dim it wasn't worth the bother (and it took a while for an electronics fool like me!). No resistor was necessary (I think?) due to the led's in the circuit.
Photos of construction are in the link - www.flickr.com/photos/repeater1/sets/72157626908216867/wi...
Presumably I need brighter lights? However, I am already running against 18V - how do increase brightness without increasing this?