I think I'd prefer more recessed toggles like your inspiration photo, or maybe even something like slide switches, just to be a little more streamlined to the shape of the case. Likewise, I'd prefer to flip them side-to-side rather than up/down. The idea of indicator lights is appealing too. Would offering different modules be too ambitious at this point? Either way, I'd love to see how this turns out. My wife has fond childhood memories of playing games on her uncle's C64, apparently.