I have the Sound Devices 788T that I'll be using to make my film. What camera should I get to go with it? I'll probably just set it up somewhere so it works while I'm using the 788T.
That's akin to asking what car should go with the TV.
788T is professional grade audio gear, so any professional grade camera would be a good match. What camera to use depends on the look you want and what kind of story you're telling.
Since you're taking advantage of using a great audio recorder, then i would recommend taking a look at the 7D. Affordable, will give you great quality, and you're going to be recording audio externally anyway, then may as well not pay for a video device that is equipped with XLR ports.