I am wondering if it is possible to get smaller bulbs than 400 watts and use more of them, and make these lights closer to the tops.
Yeah that's why I initially brought up the cobs. You could run a ton of individual lights at say 50 watts each, but if you used HID I think you'd need a separate ballast for each bulb and that would become a pain in the butt really quick. But with COBs it's simple enough to do once you understand the driver and wiring concepts, and you can get cobs in different spectrums, 2500k (same as HPS) up to 5000k.
I am wondering if before this is all over with that I have to have a metal fabricator to make a hood that would allow all the lights, with sockets placed where we desire. You got some really good links to science and that says a whole lot about you, my articulate new friend!
Hit up one of those cob builder guys. They design framework for stuff like that all the time. I know I already mentioned timber grow but there are others like johnson grow lights (horticulture lighting group), cobkits.com, & heavenbright. There's a guy on youtube called growmau5 that has a bunch of tutorials & always does various framework builds. The angled aluminum framing is easy enough to work with.