I've played around with it a little bit. I've always had a bit of a green thumb, and I've been using my tank water to water my plants for years with great success. I had a nice big Pothos growing in my ray sump (it was actually Chen who pointed me to an MFK article on the aquaponic value of Pothos), but I was finding the increased light needed for the ivy was actually causing an algae bloom in my pond.
I have thought about growing some leafy greens and zuchini using a standard stacked tank aquaponic set up, especially since I feed alot of my plecos with these same foods. I guess I'm just lazy as I've never got around to it lol
If you're really interested in it, Scott, there's a guy on GTAAquaria who's right into it. Forget his name, but search aquaponics and you'll see a slew of his threads pop up.