Here's a picture I found that might be of some help:
This is not my tank, it's from someone on Reef Central. Anyway, you see how the back glass is notched and the external overflow box is made and attached to the tank. On extra precaution I would do is to the tank above would be to add Euro Bracing around the top of the tank just for a little more strength.
Also keep in mind that if you would like your return lines come in from the bottom of the tank (like in the picture you posted) you will need to run these lines from a closed loop or else your tank will completely drain in a power outage.