I'm wondering if a frag tank could be done with a built in sump, like a nano. Have water cascade over a baffle into a three part sump and pumped back up to the other end of the tank. That way it is all self contained. Put a little mini skimmer on one end. Wouldn't have to be a big frag tank because I am not trying to sell. Maybe 2'x2', then extra foot for the sump section.
I also need a ten gallon storage container for ATO. I don't have plumbing hooked up to my tank and my wife hid my drill so I can't run water lines through the floor. 10 gallons would let me go away for the weekend without worrying about the sump going dry.