Coming back to na5m's original question, perhaps something like this might do the trick. The idea is to use
printf(1), which does support octal/hex notations, to write the sed command, and then use eval to execute the command:
Code:
eval $(printf "sed s/gratefull/grate\xYYfull/") document.txt
Here, YY represents the hex digits of the char you want, so you can specify it by number rather than some keysboard combination.