I have two different species of Spathiphyllum (I think) coverted to FW use already, per your previous advice. Your right about it growing easy. My smallest tank doesn't even have a biofilter it has propegated so well. I am slowly caring less and less about hard scape and planted tanks and moving towards these setups. Beauty and function in the same package.. It really makes me wonder why more people are not headed down this path? It's very rewarding.
Instead of using planters to grow the plants, I build a "wall" from a 3D background for the plants to grow behind. It does not look as nice but seperates the two concepts well. Have you ever considered trying that? I bet with your eye for scape and knowledge of plants you could put my tanks (already do) to shame. Or smhame them a little more lol..