MacOS will be resolution-independent soon
If your using OS X 3.9 and QT 6.5.2+ with a Quartz Extreme supported graphics card it already is. Everything you see is OpenGL. The one snafu is for those who select anything to render as "Full Quality" as that is what you get. Full Quality is the highest quality the computer can
. You want to avoid this as you will be struggling with image quality issues especially if you are using a laptop or only have a small display connected during the render.
Unlike the days of old when you just selected a larger display in preferences while rendering the OS uses multiple virtual displays and you are limited only by the size of the OpenGL texture supported by the GC which for many "normal" cards this is 2048 in any direction.
If your goal is a higher resolution than the
display supports never select "Full Quality" anything. Full quality is up to 1920x1080 depending on the connected display. i.e selecting Full Quality 1920 x 1080 on a 15" MBP will get you an image of 1440 x 878 (900-menu).
As a MBP 2,2 (ATY, RadeonX1600 256MB VRAM) user I am limited to 2048 x 2048 for rendering to a file but could never display the entire content on my machine as it exceeds "full" quality. My GC can actually support 2056 x 1600 physical display but the OpenGL texture is limited to 2048 in any direction.
You should be able to change the default size of the menus and tool bars via the command line or a property list editor (easier). I have not tried this with AC but have done so to get rid of the menus and pallets in some other apps.
defaults read com.graphisoft.ArchiCAD will show some of the defaults but menus and tool pallets may have their own property lists. Maybe someone here knows where.