Thanks for your feedback [:)]
To let you test more easily the com.eteks.sweethome3d.resolutionScale feature, I prepared a x2 scale version of the user interface that you can run with this special Java Web Start link. Under Linux, it also uses an other look and feel because setting size fonts don't have any effect on the default look and feel.
The Java Web Start link doesn't seem to work properly under Mac OS X, but it's not important on that system, because Retina HiDPI screens are already automatically managed in Java.