That's a huge thread, but from the pictures on the first page it looks like his sump will just overflow if the pump stops working... Unless there are things going on which can't be seen, I don't see what would stop the water from flowing back into the sump from all of those outputs.
But this has gone off in a different direction as I'm not setting up a sump anyway
The stand will not only have doors/shelves under the tank, but on the left side of the tank as well... I modeled it in 3D at home and will upload the render later but i'll see if i can show the general concept.
Tank stand
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Drains to the left through the left cabinet...
If I do any kind of sump it will be for ease and to hide things and it will be above the tank in the left cabinet with a bulkhead plumbed to drain back into the main tank, not under the main tank...
and the tank looks like this
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hahaha yea, it would be much easier if i could upload images, but firewall at work is not very friendly
Heres a good thread on how another member has set up his sump and closed loop.
http://www.aquariacentral.com/forums/showthread.php?t=161222