you can do it .. and it can be done quite well too. I'm using the 150watt bulbs ... 6 of them = 900watts... some of the bulbs are a little older than others.. so i'm sure it's probably closer to 850watts now. with 3 100 w incandescents in there for some additional red spectrum light.

http://boards.cannabis.com/showthread.php?t=17014

is the link to my grow board.. if you want to see some good CFL results and setups