Looks awesome man! You still got some time to wait but should have decent yields. If I could make any suggestion it would be get rid of the 5400k and 3000k bulbs and use some 2700k instead. In fact the majority of your light should be 2700k. I use 250 to 300 cfl watts of 2700k and 50 to 100 cfl...
Honestly I don't think it's a huge deal either way. I did 24/0 light for my last grow and this time I did 18/6 and I didn't notice any major differences. Besides the way the different strains looks naturally.
here ya go http://www.amazon.com/gp/search?rh=i%3Aaps%2Ck%3A400+watt+cmh&keywords=400+watt+cmh&ie=UTF8&qid=1316662437&ajr=0#/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=150+watt+hps&rh=i%3Aaps%2Ck%3A150+watt+hps you cant beat amizon
If you do decide to go with cfls buy them from amizon.com they have the lowest prices that iv found and trust me iv checked everywhere. you can get 150 watt bulbs in a 6 pack for $50 for 2700k. The 6500k are a little more expensive but you could get 6 150 watters for no more than 80.
You shouldn't have a problem growing 8 plants in that space. However, need more details. Your biggest issues are going to be with light and heat. What type of soil and nutes are you planning on using?
Ever herd of a air cooler? They use cold air to cool the air. There cheap and easy to make and i'm sure you could make one to warm the air just as easy.