Is there an equivalent to Win-P (Switch Video Output hotkey)?

If you have a Fn key on your keyboard, chances are good that some of the remotely intelligible glyphs in the same distinct color as the 'Fn' key already accomplish what you seek for, you'll just have to hold Fn and press F10.

For this to work, your laptop vendor must have its entry at /lib/udev/keymaps and udev must correctly detect your keyboard type.

For example, doing a grep -r switchvideomode there yields:

./module-lenovo:0x6 switchvideomode # Fn+F7
./acer:0xA9 switchvideomode # Fn+F5
./samsung-other:0x82 switchvideomode # Fn+F4 CRT/LCD (high keycode: "displaytoggle")
./fujitsu-amilo_pro_edition_v3505:0xA9 switchvideomode # Fn-F3
./fujitsu-esprimo_mobile_v5:0xA9 switchvideomode
./module-sony-vgn:0x11 switchvideomode # Fn+F7
./module-sony:0x0B switchvideomode # Fn+F7
./dell:0x8B switchvideomode # Fn+F8 CRT/LCD (high keycode: "displaytoggle")
./dell:0x8F switchvideomode # Fn+F7 aspect ratio
./dell:0x9B switchvideomode # Display Toggle button
./olpc-xo:0x69 switchvideomode # Brightness key
./module-ibm:0x06 switchvideomode # Fn+F7
./oqo-model2:0xF0 switchvideomode
./onkyo:0xF5 switchvideomode # Fn+E
./lenovo-thinkpad-usb-keyboard-trackpoint:0x90016 switchvideomode # Fn+F7
./zepto-znote:0x93 switchvideomode    # Fn+F3 Toggle Video Output
./ibm-thinkpad-usb-keyboard-trackpoint:0x900f2 switchvideomode
./fujitsu-amilo_pro_v3205:0xF7 switchvideomode # Fn+F3
./lenovo-3000:0x8B switchvideomode # Fn+F7 video
./hewlett-packard:0xEE switchvideomode # FnF4

Otherwise, you can write your own taking the nearest match as a template and maybe submit it to canonical's laptop testers for inclusion.

Not sure if it's the same in Ubuntu, but in Debian KDE it goes like this:

System Settings -> Shortcuts & Gestures -> Global Keyboard Shortcuts -> KDE Daemon (from drop down list) -> Switch Display - map to Win + P or whatever you want.