[hahnmeister]

Does it have to be the entire left side for viewing? The box could be just 6" thick. A box could be put into the center as well. Or, heck, your 'coast to coast' could be cut short on the ends, and instead have the boxes with their own dedicated external section on the back of the tank. Or, like you said, tunze-rocks. Also look into the Reef Ceramics, that is how Iwan did his. I like them because the tunze gets placed up high, on top of a rock rather than under one. This makes it alot easier to get at for cleaning, and alot easier for arranging in the tank.

You could have Reef Ceramic pillars that would have compartments inside for honding streams. Then you could mix the pumps right in with your liverock, but be able to get them out easily (for cleaning, which you will want to do every few months).