Mother plant areas are cheap to build & operate since you don't really have to be concerned with growing it big or potent, you're only gonna pull clones off it anyway. You can get a 2 bulb shop light from home depot for $20 and keep them alive with a couple of fluorescents. You don't have to worry about temp, humidity, or fertilizer nearly as much, just check on them when you water them and if they look a little droopy then add a little grow fertilizer or adjust the temp a little if it's too hot or too cold. You will have to balance the PH in the water, but that's about the only thing that you have to really pat attention to, within reason of course.
I'd save the 400 for the veg room where you grow plants to flower.
Also it's a good idea to keep 2 moms for each strain that you want to keep just incase one turns male or hermie.
If you're just looking for a cheap 1000w to get you going, and you can deal with the heat caused by a crappy hood, then HTG has one for under $200. Heck of a deal and if it's good enough to get you started then it's a great deal.
What you're talking about is called Gorilla Grows, they've been really cracking down on them in CA and are using airplanes to spot them. It was covered on one of thsoe "marijuana inc" shows on MSNBC (weekends). So I guess they can be good if you do them in the right area. But dude seriously, these days a military base is the last place you want to be anywhere near for a gorilla grow or even to just burn a fatty. I'd pick a different area to be on the safe side, domestic base security is at an all time hi right now. Plus if it's a military base you never know if they might be experimenting with something that can kill your plants or you for that matter. Radiation is a bitch. lol
And there is one thing you should know about gurilla grows. Every one they found had a shelter built near by so someone could stay there for days at a time. The reason is when your plants need you, then you need to be there. If they get sick, have infestation problems, flowering starts and you have to pull males, etc... then you might have to spend a few days in a make shift shelter. Not only is this no fun to people who don't camp, but if you're in Cape Cod then you have to worry about bears too, especially since you'll have to bring your own food to survive on while you're there.
If you pick a better area and carry a gun big enough to hurt a bear, then you should be ok. Just remember to keep your food off the ground, it helps keep bears away.
Also you may want to look for some books. I never read up on this myself, but on the Marijuana Inc show they were showing irrigation systems powered by gravity that allowed them to grow miles away from a water source to make the grow harder for the cops to find.