I also have know familiarity with fallout, but I think I have an idea that may make your already great looking art seem less repetitive and allow you to group the controls.
I would leave the marquee as is.
I think it would be cool if your side art was either the full size of the cab (probably way expensive), or fit into a more pleasing shape than the rounded rectangle. I would suggest that it be cut right along the edge of the symbol, but then what to do with the cool blood? Maybe you could make the side art background more poster-like and fade the edges to the same color as your cabinet? Or maybe move the blood to the CPO and cut away anything that is the gray background stuff leaving just a little bit as an outline around the rest of the art. Mostly I just think that the rectangle makes it look like a sticker on the side of a cabinet, not part of the design of the cabinet.
I would take the title and thumbs-up-guy off of the CPO, and use the wings from the side art to wrap around the trackball. To make the control groups stand out I would put them in outlined areas that look like the title graphic, it's already the right shape even, just backwards. I think that the colors and patterns would make the whole thing work together and seem cohesive, while removing the title and guy from the CPO would keep it from being redundant, or over used. I do like the idea of using the guy for the player buttons though, you could even just use vinyl cutouts of a thumbs up for P1 and two thumbs up for P2.
I think I'm going to have to check out fallout, if the idea of your artwork was to advertise a game I think it would work great, I think with or without my suggestions you will have a cool finished product.
Edit: spelling and to say that the website for that game has some cool graphics, I like the mix of retro propaganda cartoon and nuclear aftermath.