yea the plan is to grow in a small crawl space. It's about 5 feet tall but it's also like 8'x8' feet so it should do. I just don't really think there's a way to get rid of the heat though, otherwise I'd be down for MH/HPS in an instant.
this one...
Procyon-100 100W LED Grow Light - HomeGrownLights.com
and this one...
LED Grow Lights - LightBlaze 400
are supposed to be pretty much the same and both of pretty decent quality. obviously the best LED set up would cost close to $1000+ but I'm sure the quality is close to being great for $600. You could think of it as ventilation being included in the initial cost of the light considering it doesn't need any!
edit: then again if I grew in winter and it was naturally pretty cool down there that time of the year, would it be okay to use a 400w HPS in that small of an area?