I'm running a T5 x LED hybrid and like it. I'm not well versed in the LED electronics or aluminum thermal dynamics so I can't help you there. I got my LEDs from LEDgroupbuy.com and really like the LED drivers they sell and the customer service is second to none.

Personally I would not mess around with aluminum sheets... get some heatsinks from heatsinksusa.com or keep an eye on the forums for someone offloading used ones.

Tom