I like this setup Scott. I'll second the plexi idea, but you could also use old storm windows? Fans are available lotsa places. If they'll be getting wet, avoid the 120 volt models. They are also louder than 12 volt. Small 12 volt fans are available from
Coralife 3-1/8" Cooling Fan Kit
I personally prefer the artificial lighting option for a couple reasons - it is easier to control (not at mercy of sunny vs cloudy days, etc.) and you can control day length with timers. Home Depot shop lights are good enough for lots of spp - don't need fancy. Cool white t8 bulbs (the skinny ones) are pretty bright. Let us know how it works.
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Ross
http://orchids-ross.blogspot.com/
I don't do most Dendros or large, "floofy orchids". For me it's minis (like Angraecoides), Masdies, Paphs, and others that crept in somewhere along the line. See my orchid list for complete collection (usually not current.)