Ok, I just measured a different part of my home, and these are the dimensions I can work with for a mostly-stealth cabinet.

36"W x 26"D x 36"H. I really think 400w - 600w HPS is going to be the maximum I can afford. It's looking like that is going to cost around $150-$250, without bulb, depending on where I get it. Any recommendations as to where and what to buy? Most of the aquarium ballasts and whatnot are way overpriced, but those are the only places I know to look. It doesn't have to be fancy, so long as it is a quality unit and utilizes a remote ballast.

Would two plants be too much or too little for this size? I'm going to go ahead and try a SCROG, maybe slight arena style.

Since this is kind of a custom box shape now I don't think I'll be able to just buy a cabinet at a hardware store. I figure I can build it out of particle board easy enough, though I have no idea how I'm going to make it look decent to be stealthy. I think anyone with half a brain who saw it and heard the fans would have an idea what was going on.

Also, I figure 400w, plus good airflow through the box itself to keep the plants healthy, plus having to overcome getting around leaves and stems and screen is going to take a lot more air than I am used to using on aquarium hoods. I think I'll plan on about 400cfm through the box. Does this sound about right?