I have some info on my blog. I would recommend t5 HO florescents (probably either a single or maybe a double tube fixture. No need to "swamp" that little tank. I use 4 tubes on mine which is 32"Hx36"Lx 20" thick. The height will be your most important measure. I read approx 800 FCs near bottom of mine. The lights are hung approx 4" above the top of tank thus the bottom plants are approx 30-32" below lights. 800 FCs is pretty dim. Not many bulbos will like this little light. A couple will. For your suggested tank I would suggest
New Wave T5 Fluorescent Grow Light 4ft 2 Bulb 108W which includes the bulbs. I would go with the 6500K bulbs. Just my 2 cents. I try to provide around 5500K temperature since that is close to normal light for viewing plants. The plants will do just fine with the 6500K tubes. Keep in mind these fixtures (the t5 HO fixtures) run at 95 degrees F, so temperature can get to be an issue. The best way to control temps is get the heat away from the tank before it gets in there. This is my setup:
Hope this helps. Feel free to question what you want and to check out my blog where I go into a lot more detail. I also have a "front page" article on converting an aquarium to a Orchidarium. Check on main Orchid Board page under articles. Can't think of any artificial lighting I haven't had direct experience with except LED.