Well, I think you might find the price of LEDs to be prohibitive. Consider this:
The cost of a California Lightworks SolarStorm 800w is $1,600 shipped from a 3rd party site. Its actual operating wattage is around 640w.
640w / 40w = 16, so each SolarStorm 800w will cover 16 square feet (a 4'x4' space).
144 / 16 = 9, so you will need 9 SolarStorm 800w lights for 144 square feet.
9 * $1,600 = $14,400.
OR1000w HPS / 40w = 25 square feet
144 / 25 = 5.76 (round up to 6) HPS lights.
6 * $500 = $3,000.
$500 is a reasonable estimate for a complete 1000w HPS setup with ballast, hood, and bulb. Of course, there may be extra cooling costs, but nowhere near the difference of the two total prices ($14,400 - $3,000 = $11,000). Yes, $11,000 in savings in lights alone if you go with HPS.
Also, if it is true that 1w of LED light grows the same amount of veggies as 1w of HPS light, there is no savings in electricity. Therefore it's no better for solar power, and it won't lower you electrical bill.
Double check my numbers for me, but I'm pretty sure that LEDs are waaaaay too expensive. Having said that, I'm waiting for my first LED light and I'm going to try it out for myself.
Hope this helps,
Dave