It's there! A daring:
avrdude -p m8 -c usbtiny -u -v -U lfuse:w:0x1f:m -U hfuse:w:0x40:m
has run, and now I lost my hardware reset capability - and won the PC6 line so I can use modifier keys in addition to all other keys.
It's still a bit flaky now and then, but I was able to type this blog post without much trouble (except for the spurious Ctrl+A every now and then, that was quickly to be fixed with a Ctrl+Z...)
Even duckduckgo'ing for spurious using the ctrl+t, tab, enter, ctrl+w and the selecting of full words using ctrl+shift+arrow all work! Woohoo! :)