i wonder why you wouldn't have noticed, but bitzi's bitcollider does (among other things) exactly that...
just try something like:
bitcollider -q -p file.ext 2>/dev/null | grep tag.uuhash.uuhash | cut -d= -f2
if you need more efficiency, you could easily strip it down to only calculate the ftuuhash... or wait for a version that supports selecting what to calculate (sometime this millenium)