Thanks for the swift responses guys,
In the theme download manager of BigBox, there is a meta text for this where most themes are showing as supporting any aspect ratio. I'm asking there be more diligence in making this accurate in spite of the fact that it may be unusual. Most go with a Raspberry Pi, but Arcade1UP's have plenty of enthusiasts looking to trade out that hardware with a PC running LaunchBox/BigBox, and there are many cabinet enthusiast who prefer the authenticity of a 4:3 monitor or CRT.
Best,
Grant