Does anybody know how to configure the status bar (bar size, icons and font size, and so on)?
I'd like to do it while keeping the screen resolution, of course.
I've browsed and searched both Ask Different and the web to little or no avail.
For the most part the menu bar has no configuration options in respect to font, size, etc.
You can however manage the icons in the menu bar by holding command while clicking & dragging them. This allows you to re-arrange the icons or drag them off the menubar to hide them.
As others have suggested, I'd encourage you to submit feedback to Apple regarding any customization changes you'd like to see in future versions of the OS.
The Finder status bar is currently unconfigurable. You can provide feedback to Apple here: