After a top of the range dawn simulator? The Philips HF3520 Colored Sunrise Simulation Wake-Up Light could right up your street. It offers a range of light intensities, nature sounds and an FM radio amongst other things.
The Carex Day-Light provides a whole lot of light - the lightbox is 16 inches wide and 13 inches tall. It also is easy to set up so the light shines down onto your eyes to get your light therapy in the optimal way.