For under $400, you could look up:
Area 51 RW75 or W100 (
http://www.a51led.net)
Any Hans panel in the range (
www.bonsaihero.com)
Kessel up to 4 H150 purple or magenta or a single H380 (
http://growershouse.com/lights/indoor-led-grow-lights?c2c_brand=7925)
..... or you could go generic with something like a Mars Hydro panel, which seems not to be recommended by the more technically savvy members here, who might tell you to go with Cree bulbs for less money anyway (right
@az2000 ???).
You could probably get coverage of a 3 x 2 footprint with 2 65W Hans Panels ($460 for the 2 with shipping), but I don't think they would give you penetration for tall plants in an 8ft high space. Might be nice for short indicas or maybe you could add cheap side lighting, like AZ and Captain Morgan.
From reading the DIY threads, I would guess you could get some nice components with that budget if you have the skills/desire for that.