'Commercial' scale indoor setup - ideas?

[littlefrog]

Another thread got me thinking that I should pick your collective brains... Here is the deal. I've grown in a 1500sq foot greenhouse for the last 6 years, with only a few plants under lights inside. Before that, for many many years I grew exclusively under lights.

We are moving (have moved) and due to my township being obstructionist, I've decided to convert my new pole barn into a growing area. Or at least part of the barn. It has its own electrical service (200A), mostly concrete floors (two corners are dirt - used to be horse stalls), and it is insulated with whatever insulation they use on pole barns these days - some sort of thin radiant barrier type, probably not a huge R-value but better than glass for sure. Barn is 48' x 30', I'll probably be lighting about half of that right now. There is a smallish gas fired unit heater in there already (going to try to hook it up next week), and I can build a dividing wall pretty easily so that I don't have to heat what I'm not using. Open ceilings so I can mount lights as high as I want.

So... For growing orchids and bromeliads, which have a moderate light requirement, I'm planning on using a few 1000W MH lights. I already have two 400W MH lights, I'll add those into the mix. Right now I'm trying to figure out what kind of square footage each fixture will illuminate, and at what height.

For growing the foliage plants (ferns, various small tropicals), I was going to go back to light carts and fluorescent fixtures. I have lots of T8 fixtures, but since I'm spending money, I have considered upgrading to T5's, but I'm not sure if it is really worth it.

So, given that background, do you have an opinion about what you would want in that kind of facility? What might you do that I haven't considered? HID growers, how high and how much area can I really light with those fixtures? Basically if you have an idea, I want to hear it before I start building this beast.

THanks

Rob