So as a compromise since I cannot do this references, I have a displayable created by an enumeration. This should work and have it how I want to do but not be a completely unsafe or edgy thing to implement (like an abstract create whatever method).
And I just ran into the singular inheritance limitation. Likely the best way to handle this is to have a window which can be specified as a container for the native widget. So basically the Swing code creates a class which is just a JFrame and all the special handling logic in that. Then the native display will just say, use my container.
Actually the window can be handled by the display itself rather than the individual displays because only a single display maps to a single window.
So basically the head will have the maximum size and then the content size which might be smaller than the maximum size, it really depends.
Now that I got a new base for LCDUI I can get back to what I originally was going to do and that would be fonts. Fonts will just be images, but they will be linked to native displays and such.