I saw in the Tau of Composting chapter, a note that people sometimes think that flush toilets are superior to his method. And I really must confess, not yet being into composting myself [city dweller], that I don't understand why those two are opposites.
Couldn't you have a flush toilet, run it from there to a septic box, harvest the solids for compost once a year, and let the runoff grey water compost in the style of Buckingham Palace's stream septic system?
Yes -- it would be more expensive. But with a better designed system, I tend to think that it would become acceptable even to the less humble.
[ps... I probably won't come back here. If you reply, please also cc: me at DSCPUBL "at" siltec.lt]