Why yes. In a nut Shell- Escape to Shell shortcut!
You don’t know what it's like,
if I wander over to the giant movie Start Screen.
It's so big, looking from first row, that glasses not required.
So when I get totally dizzy in there,
I click the Escape to Shell shortcut, and say three times "there's no place like home",
and I'm back safe at home!
Seriously, it can be done right now - the shortcut tile, though not the internal live part.
Just have to download one of those start screen "Show Start/ Start Menu button.exe files from net,
use it the opposite way it was intended.
It was made as a visual clue to get to Start Screen. We can use it to link back to Classic Shell menu, instead.
All it does is emulate hitting the Win"flag" keyboard key.
After downloading the file, unzipping it, just right click it, when in desktop mode,
select "pin to start". Then delete the .exe file, if not required, as CSM provides similar button,
There will now be a shortcut on the Start Screen that will take one back to Classic Shell.
Hip Hip, Hooray!