Seeing as this is my first real grow room, I'd probably start slow and if I am successful increase the size. If it's possible I'd probably just have a 10-15 plant start up (one section with flouros for vegging/growing) and one flowering section with some kind of HID I guess. I was thinking soil, but I've also considered Hydro.

I figure if the ventilation wasn't a problem I could make a little chamber using insulation on the floor and getting heat from the lights and if needed heat lamps.