I basically did the same thing. I wanted the unit self contained (clone, mother, flower, veg). Mothers will be above and below the shelf in the right of the veg chamber. I like sativas so my cabinet is 6.5 tall which allows for 4.5 foot plants. Total demensions 6ft wide , 2 ft deep, 6.5 ft tall. You could make a similar cabinet out of wood maybe that would be 4.5-5 ft tall and use a 400 HPS. Im sure once dialed in you would be able to pull 10-12 oz every 60 days using scrog.
With no C02 or fancy electronics i bet the whole project including nutes for 1-2 grows would come to 500-700 $ total.
I see you want to use cfls. I hate cfls but if you are stuck on them i would do more smaller plants. Why not get a real light? It will save you money in the long run and increase yields. I also feel 1 larger light is easier to deal with in terms of heat then many smaller lights.