I like the shelf idea. You could still make it nice & clean looking even with a shelf. And I think a shelf would look cleaner than a strap.
The hanging/floating tank looks cool but would make me a little nervous. Even with only 4 gallons of water in there.
Another update.
Yesterday the glass pieces I order were ready for me to pickup. So I picked them on my way to work. After work I used a red sharppie and mark line on the out side of the tank where I was going to put the baffles in at. Then I put a small bead of silicone on each line one baffle at a time. I slowly put each baffle in and used my finger to smooth the silicone. I finished the sump around 6am. Had this in the morning.
Then this morning I replaced the side pain of glass I broke when taking off the trimming. After about 4 hours of letting the side panel silicone cure I painted the back and bottom pains. This weekend I'm going to do a fill test on the sump to make sure their r no leaks. Cus I basically re-siliconed the whole sump.
I didnt want any thing to not give the silicone the best possible stick. I also cleaned the entire sump with rubbing alcohol before starting to silicone.
I was impressed that Derek had this same screen on this tank with out a skimmer and was having great result when he kept up on the cleaning of the screen.