Selden, that's pretty much the direction I'm going in now. I've been working largely on the conceptual end of the game (rules, game mechanics, basic perspective), but I have an associate with a strong background in graphic compositing and animation. He realized the simplest way to go about it, is to create a cube as such, but place the virtual camera from which the player views the world inside the cube. That way the screen is always completely full of spaces, and the image distorts realistically around the edges as you pan. We still have some tweaking to do with the camera's lens, but it seems to be an extremely elegant and flexible solution. I'll post pictures when things start to develop more.

I really appreciate all the feedback from everyone. Some time down the road I'm also going to need a play-testing team. We worked out most of the game mechanics in an earlier, completely 2D version using GameMaker Pro, but we're adding the extra 5 cube faces for a new version using the Unity engine. I'm hoping to have some rough Beta in a month or so. Once we get over this initial 3D hurdle, most of the work will just be translating the scripts we were using before.

I only stumbled across the Guild a few days ago while trying to figure this problem out, but I can already tell that this is quite a nexus of creative minds. Thanks again everyone.