Defenitely possible. I've seen some really nice low-light tanks that look alot like that. Just throw in alot of anubias in front of a piece of driftwood that you plant java fern on and all of a sudden you have a really interesting tank with no hassle. If you want to go with more variety of plants such as the red ones and everything then you're going to need more light, around 25-35watts and eventually introduce CO2 somehow. I think some members here have ~5g that light them with mini Power Compact Flourescent lights.