A few things to consider...
Those bulbs are 3-4 lumens (amount of light) and cost $2. That's as much as 200 times less than the intensity of a single 100 watt incandescent bulb.
Sure, they only draw .06 watts so you can add lots but not at $2 each. To get to a typical grow light intensity of 8000 lumens, you'll spend $4k. Even CFLs will run $2k but there's a different problem.
One wonderful thing about LEDs is that they produce only one exact color. Plants totally ignore all colors (like green - they reflect it) that they don't use. So why spend money giving them anything but royal blue, dark red and orange-red (430, 620 and 660 nm)? When buying grow lights, just buy those colors and save cost, wasted heat and power.
I went through this 2 years ago and found that the product offerings was lacking in those colors but now there are many more options. There's also much higher output - they're approaching 200 Lm/W. Price is plummeting and others are beginning to make very creative assemblies to put them together. I originally paid $500 for 104 watts, yielding 8,800 lumens in just those 3 colors. A quick search finds that prices are half that and power consumption can now be 60% of that.
Normally, this much light would cover a smallish grow bed if it was laying flat. The system I'm using in the OP actually wraps the plants around the light and rotates them hourly. This provides light to roughly 3-4 times the number of plants. In essence, I get 120 sq. ft. of 'footprint' covered by a light designed for about 6-8 sq. ft. It's pretty cool, but best of all, it speeds the growth up as much as 3-4 times as fast. Not bad when you're indoors and aren't restricted to seasons anymore.
Here's a few links to get you thinking. Reading a little first might help understand how it all relates. Hopefully soon, you can simply buy it complete.
www.omegagarden.com (look at the FAQ regarding light coverage and 'orbitropism'.