how about either two 600s or a 1000 and a 600? I have a tent that size and use two 600s and a 400, with one of the 600s using a mh bulb and like that pretty good. As far as lumens per sq ft, i have heard a lot of numbers for what you want, from 2000 lumens / sq ft i think being the lowest i have heard recommended to i think 8000, and i heard sunlight is 10000 sometimes i think. I like having multiple lights for a lot of reasons and didnt really think the extra initial cost was much of a factor.
As far as fans, I have 2 6" (450cfm) fans that seem to work pretty well, both run thru lights and one sucks thru a charcoal filter from the room. I think you could get away with less veg room if that is the only flower room you have to grow plants for, and use the extra room for flowering, depending on how you set it up. I think 3x5 would be enough. It is for me at least for my 50 sq ft of flowering space. Be sure to run your room a couple days to make sure its not getting too hot etc before you put the plants in, and get a thermometer with a hi/lo memory and make sure you have a good fan blowing on the plants.
What kind of veg light are you going to use?