Then there is always the option of custom building your own.
A year ago I set up an odd shaped nano aquarium - 12" x 12" footprint but 24"deep. To get sufficient light penetration down through 21 to 23 inches of water column I built a light using a combination of CREE x-pg and x-ml LED units. Plant growth has been explosive. Specifically my photon hungry carpet plants at the bottom loves it - I get pearling within an hour of the CREE x-ml's kicking in.
The latest batch of CREE x-ml LEDs can push out 1000 lumens per unit, and their prices dropped significantly - $6 to $8 a piece. These are available in cool white (~8000 K), neutral white (~6500 K) and warm white (~5000 K). Mix these up to your preference and you'll probably end up with a better light than you can buy commercially.
Of course this DIY approach does require some electronics and electrical skills...