There is another post here under snakes for the rough green. I think this is the one.
Rough Green Snake
hope it helps.
And beckdg, I agree I'm a firm believer that larger is better as far as enclosures. The more room they have to explore the better, not only does it help excerise (helps combat obease snakes) but it better replacates the enviroment for them by placeing rock's tree's and such. That not only helps them feel more at home but it aids in the health of the snake.
Oh yea if you want to have a small enclosure for a small snake (though he likes to hide alot) check out sand boa's. They look like large earth worms. LOL