Have you seen the small CNN documentary video about the Dervaes Urban Homesteaders (of Path to Freedom fame)?
If you’ve followed the Urban Homesteaders, it won’t show you much that is new, except for that toilet/sin (approx. 2/3 into the video)!
The lid of the toilet water tank has been converted into a small sink. You wash your hands with new water and it drains into the water tank. It’s perfect!
Theirs seems to be a Gaiam system (picture above), but for the do-it-yourselfers I found a quick hack here. A more elaborate system that stores the drainwater under the usual sink and diverts it to the toilet can be found here and here.
No need to flush perfectly good drinking water down the toilet!