Well it's finally finished, big thanks to Old-Lumens for inspiration and to TechJunkie for his help in the electronics side.
The Light is a 3d Mag driven by 4c cells using techjunkies AMC 7135 board master/slave mod. I've used 3 xml U2 1C (i think) leds all driven to 3 amps using Kaidomains V2 of the AMC 7135*8 board
Leds are from LED-TECH.DE they are very well made and are fitted to a lovely copper star.
Good question :) well until i can find a better solution i've just used some cardboard to make a sleeve around each battery, thats stopping them from rattling around.
Heatsink is fro Derwichtel from CPF its a very nice piece of machinery and i highly recommend it and any of his heat sinks, in fact i've used his heat sinks for my last 2 mag mods :)
I think you can find PVC that will work, if you have a good hardware store locally. If not, you can use the plastic sleeves that protect fluorescent bulbs. They are easy to cut with a hot razor blade and you can use a couple layers of it, to take up the space. You can get it wrapped around the batteries and heat with a hair dryer, to form the stuff. Not too hot though, or the battery wrap melts. Or just use something like a dowel, that is the same OD of the batteries, to form the sleeves around.