It doesn't matter what the tent looks like really, what I was talking about was the negative pressure issue. You want your tent to at least be trying to concave in because that means that the air is being pulled from it (and not leaking out everywhere there's a hole or airway). Unless your running a completely closed system this is good because you can control the air if the pressure is working with you, when the pressure is positive then the tent will bulge and stinky grow air will leak and smell. If you had something pulling air out and running it through a scrubber then you would have more luck keeping that aspect in check.
I think I was actually wrong with my initial question though, if the cooler that Green Rev was showing us was only circulating air in the tent and not pulling any from the outside then I can see how the pressure might work out. I think with a few ona blocks scattered about you'd be hard pressed to do better than a setup like that. I'm going to look into it; I'm already running a dedicated air conditioner just for my tent now anyway, so I don't see how this would be very different besides being even more enclosed and ready for c02.... that's my end goal, adding co2 to my setup.
