I HAVE POSTED THIS BEFORE, though i do not recall what thread.
My composting toilet is a www.biolet.com. It does not incinerate,
but has a fan to circulate air, and a heater which helps to dry
and sanitize the contents. The finished product looks much like
potting soil and it gets dug in around fruit trees and flowers..
not veggies and especially not root crops! It does not actually
take up as much space as a flush toilet, as there is no water
tank or plumbing necessary. It does use electricity, though,
and needs a vent pipe. There is a non-electric model that you turn
by hand using a rotor handle--all clean, on the outside of the
unit. This would work great on boats or in cabins. maybe even
in an R.V.! Some time back there was actually an office in the
state of Calif. called Appropriate Technology. This was when
Jerry Brown (bless his heart) was governor. Sim Van Der Ryn was
the official in charge of that office. He wrote a book on
composting toilets, "privy" and other alternative ways to
deal with shit. It is called the Toilet Papers.
http://www.amazon.com/exec/obidos/tg/detail/-/1890132586/103-6445157-8384606?v=glance