I have now updated CarBox to allow you to stretch to any screen resolution, including all buttons and fonts etc.
It works fine, but can look a bit odd, depending on how you change the aspect ratio. Should help some people, but I think I'm going to have to bite the bullet and make skin-with-hotspots an option, as well as buttons as it currently has. I kinda prefer buttons though because you can easily move them round the place if you want.
From a skin-makers point of view, which is preferred? Doing on-and-off skins and defining hotspots, or individual buttons?