I've seen those orchiariums and all what it looks like is a sealed up box with shelves lined with myler. A glass window in front to view and enclose it. But how hard would it be to make one yourself?
Get some wood. Seal it so water won't damage it over time. Line it with myler. Cut out a hole in back so you can stick a a/c unit for the summer. In winter just open the window. Maybe have it 48in long, 24in deep, and however high you want it. Screw the lights in. A drip pan at the bottom. Up top have hooks for hanging baskets when they get lager. A fan or two for cirulation and to cool it down. Maybe some vent holes along the sides. A glass door that opens for easy access. A humidifier. A misting system would be too much I think. What would that cost? Not $2500.00. It would not even cost too much. Why use a shelf from Home Depot when this would be way better?