That is wrong. 2 7970s will be fine on a 750W PSU, even after overclock. The only reason you should get a Full Tower is if you run a true water cooling setup with 2+ rads.
Ah ok thanks for the advice dude. I might just keep it though only because I'm thinking kinda ahead for further modifications like you said water cooling and stuff. I do appreciate the tip though, I will really think about it.