Not exactly what you're looking for I think, but
I got the AHK experts here working on Win+Q a few years ago -- this was my favourite version, it opens the Window's Shutdown dialogue:
[..] if you want to update to AHK_L the hotkey can become this:
there are other variations in that thread (one that just killed everything without asking which was too much for me).
I also have Ctrl+Q to close active window (but not on this machine so cant check the script).