If you really want to have live plants, you might be able to build a plexiglass "cage" and build them in that. I think 24"x12" plexiglass is pretty standard. You could silicone a couple of them together and section off a corner of the tank for a plant area. If that works you might get fancier and cut a sheet in 1/2 and that could give you 12"x6" sections in the rear corners of the tank.