Thought I would post this here as well for anyone interested. This is a blatant copy of Ben Belton's setup that he built in 2007 or 08. It's seen here:
Big Leaf Orchid forum • View topic - My New Greenhouse!!!!!........
So thanks to Ben for a lot of the setup help. But here it is, size is 10' x 8'. Should leave enough for at least 2 4'x4' tables of orchids. The entire the is lit by 2 4 bulb T5's, and a single 400W MH. Whole setup is wrapped in 6mil painters tarp, and really holds heat pretty well (something I'm learning to appreciate in winter...). Dont mock some of the wiring issues, I'm still working on that, and a door. It'll be finished one day. Hopefully this will encourage some of you with extra space to put it to orchid housing as well.