Light movers would help immensely, would be very cost effective, would cut down a lot of your cooling needs as well. Light rails are great, you can move up to 6 lights on each, do 2-3 light rails with 6x 1000 watts on each. Either that or go with the spinning lights from Life Light Tech, check out High Times Spinning Lights article, there is a video on youtube, looks great... Other than that, if you won't move your lights, just throw a 5 ton A/C in there and pump it with a CO2 generator.