Here's a screenshot of a patch I'm working on which scales the UI for
high DPI monitors - I think it's pretty cool :-)
It was surprisingly easy to implement. The actual scaling is done
simply by changing the bounds and frame rects in
GSWindowDecorationView (no changes in -back, and it works with
cairo/art/xlib). You can set an arbitrary scale factor via a
GSScaleFactor user default. Other than that, there were just a couple
of bugs to fix to get it to work (and still some bugs remaining, but
it's at least usable.)
I'll commit this after the upcoming release.
Cheers, Eric