I've written a script that looks at the output of xrandr and reconfigures the screen layout, based on which outputs are plugged in and what the resolutions are.

I've written a script that looks at the output of xrandr and reconfigures the screen layout, based on which outputs are plugged in and what the resolutions are. This is then bound to a key via the window manager so I can seamlessly move between laptop only, laptop+1 external, laptop+2 externals, or 2 externals only with just a keypress after coming out of sleep. This has been pretty solid on MacBookPro10,2, running the XFCE spin of Fedora 21. Some people have questioned if I'm running Linux when they see this work. The background on the login screen doesn't always render correctly, but I look at that as often as I reboot (which is like once a month), so that doesn't impact me much (just like boot time, ahem). My main concern is that as things become less shell-scriptable (like requiring complex dbus interactions), doing this will be less accessible to work around design or implementation quirks to achieve the desktop experience one wants. This is the price we pay for progress, I suppose.