LED Homebrew Question

I have a close friend who works fixing circuitry and has wired LED lights for computers and other electronic devices. I mentioned LED grow lights and he said he could build a LED array fairly easily. Is this a good idea? What kind of LEDS would be need to use? He says we can take them from

UV 21 41 Head LED TORCH ULTRA VIOLET FLASH LIGHT - (eBay.ca item 270202901478 end time 13-Jan-08 02:43:13 EST)

one of these, or we could pick them up in a electronics store in bulk. Would these be the right kind of lights? Sorry if this sounds stupid.

Get some high output led!
Check out my thread!

https://www.rollitup.org/indoor-growing/40849-36-watts-led-grow-action.html

Well, each of those 41 LED flashlights puts out about 4w of light. You'd need at least 9 of them per plant IMO.

Ok so would it be more economically pheasable to let Rick build them or should I find some to buy? He said they could be built for under 30 bucks each (he said 81 LEDs to each lamp)