Thanks for the input everyone - yes, the swiggles on the side were very roughly drawn in, so it will need more attention in terms of playing nicely with the existing border and characters. I'm not sure about the color of them either now that they are plastered on the sides!
As to the control panel, there will be a 4-way and two buttons towards the top center that don't show up in the image. My cabinet will be 27" wide on the interior, so I started with the Cowboy Arcade control panel plans that I saw floating around here. I've ordered the joysticks and buttons and agree I need to make sure things aren't pushed back too far to be comfortable for playing. I really appreciate everyone's input, I think this is looking much better than when I started...