The Henry Double Day Research Association had a series
on urban shredders and mulchers etc in the early 1990's, which included designs
from various people. I seem to remember that they published a book on the
subject which may be available.
Can you find an old chaff cutter, one with a large,
cast-iron, wheel which acts as a fly-wheel? That is the closest and most
effective machine which I have seen which can maybe suit your
requirements.