I've been very happy with this trunk:
http://www.mutazu.com/products.php?cat_id=2&menu=DB%20Trunk%20Series&product_id=21&s=prod.phpThe spoiler has LED lights that chase from the middle to the ends when the running lights are on, and the spoiler LEDs all light up when the brake is applied. The two lenses below the spoiler are turn signals. Really improves the visibility of the bike from the rear, especially at night.
I have the larger one. Do a google search for Motorcycle Trunk With Spoiler to find some good deals on these.