I would go for a DIY CFL fixture instead of T5's or T8. They are easy to do, cheaper than doing a T8 setup and bulbs are way cheaper as well. I have 3x13w CFL bulbs over my 20gal, and plant growth has exploded compared to what it was before.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.
Sump Pimp #2
My Tanks and my shrimps