Containerless Grow Possible?

Hi,
I have a couple of small ebb and flow gardens (Megagardens) that are 20x20. On each I'm using 15 of the 5in square pots that came with the systems and have had pretty good success. I've noticed after harvest when I was tearing everything down for cleaning that the plants were pretty root-bound.
I'm thinking about getting rid of the pots all together and just filling the table with hydroton. It seems like this would let everything stretch out a little more.
I know I would have to build a flat tray to put under the media to keep my drainage channels open.
Any of you have any thoughts on this?

I thought about this a few days ago aswell , In my oppinion it would be good , and im planning on trying it. But im keen to see what some more experienced people have to say.

you can buy a lid for your tray and then just put net cups in.

I thought about that, and was even thinking of converting both systems to DWC.