So, bring on the molding.
All it took was a little patience and an angle finder to create this wall. You are creating the illusion of a paneled wall that appears to look like one elaborate wall treatment.
The key: Getting a balanced design, and paying special attention to how you space out the boxes and molding. Keep it simple and use the angle finder for the miters. Finish it off with wood filler or spackling to get a more precise finish with the miters. And then paint the wall.
Although I was real tempted to leave the wall tan and the molding white as I know I would never be able to paint trim that well.