Here is my Led bar, after a lot of work and patience and a flasher from Changchung, its up and running. Mind you this only cost about $120 and is as bright as a TIR6 Director.
And this is an email i sent to a guy to build it.
Ok, to start you will need:
Either 8 or 16 of these puppies (whichever you choose) Bulkrate is your friend, it is a wholesale discount, it depends on the amount of a piece you are going to buy, just remember "APPLY BULKRATE DISCOUNT"
Now we need to power the leds without OverVolting, thats where the drivers come in, you will need 8 regardless. Just Desolder the pegs and put wires on instead to your 12V (can power up to 3 leds in series)
Finnaly, the most important part, Optics, if you use shitty eBay lenses the light output will be cut almost in half compared to my new ones. The best lenses i found were on ledsupply.com, i used the oval lenses for the Cree XP-E, they create a HUGE beam spread with an intense amount of light. I wouldn't use anything else!
Use a piece of angle iron to mount on 1/8-1/4" thickness for heat dissipation .
To build this product you need patience, first of all DealExtreme is a Hong Kong based company, which will mean it willl take 2 weeks before its at my door. If you want the quick/expensive route use ledsupply (7.49 per vs 2.80 on DX)
If thier is anything i missed just get back to me and ill help you as much as possible!