As mentioned, I agree that the higher temps and light distance are major issues with what is happening here... higher temps will almost always cause slow growth, and the light distance will cause them to stretch and have greater distance between nodes.

I use CFL lights mounted in Y-splitters (2 bulbs per splitter) and then 2 pairs of those plugged into power bars. I then hang the power-bars by thier cord and lower them to where they are safe to be - ~2 inches from the plants. Let me know if you'd like some pics. =)