You might be able to buy a double bulb fixture. You could just gut the fixture and install something of your own make.
What is the width of a single side of the tank? There is a 96 watt quad bulb which is about 4 inches wide and 18 inches long and would let you grow just about anything you'd like. (HelloLights.com) You would have to build a hood to accommidate the reflector and bulb but it would get the trick done.
Aquascape? I'm a crypt farmer.
It's a fine line between fishing and standing on the shore looking like an idiot.
That IS an aquascape, it's titled "The Vacant Lot".