How about reserving unicode numeric superscript characters 0..9 as label identifiers only to be used for loop & break, etc. Then the example below would become:
while¹ not processed():
for² x in the_stuff:
if all_done(x):
break¹
It's cute. And really quite readable. But it's not writeable. I had to press 'ctrl-shift-u 0 0 B 2 enter' to fix the 2 superscript you omitted (the 'as' was still there). But that's not uniform, other people with different OS's and different keyboard drivers will need to press different combos, none of them just a keystroke. Sure, various specific text editors might be configurable to allow other different shortcuts for it, but that emphasizes the point, not mitigates it.