Kathryn has applied for a permit to build a Thermophilically composting toilet system.
The application that contains a thorough description of the system can be downloaded as a pdf Application to Thermophilically Compost Humanure
It looks like this system is going to be approved soon.
The following sites contain way more information then you would need. The State of Arizona has an aproved systems list that I have not seen yet
This site has a lot of good info on off the grid living including some basic explanations of the legalities, logistics, and care and feeding of compost toilets
http://www.pathtofreedom.com/links/offthegrid/water&waste.shtml
This site has a lot of good information it is Envirolets home site http://www.compostingtoilet.org/
Envirolet composting toilets and composting systems several low water and no water systems both 110 volt AC and 12 volt DC http://www.envirolet.com/
Phoenix composting toilet systems are waterless and use only 5 watts of power http://www.compostingtoilet.com/
Clivus Multrum is known globally and uses power only for a fan. It is possible to construct this system out of plywood and fiberglass for about $1500-$2000
It is interesting to note that Arizona tested this system in the rest areas and it failed some say because of lack of maintenance. The composting toilet at the Fort Bowie trail head and parking area is of this type. http://www.clivusmultrum.com/
The Sunmar Excel NE looks interesting check out Sunmars stuff at http://www.sun-mar.com/
Want to know more? the humanure handbook on line http://www.weblife.org/humanure/index.html
ASU's educational page on waste water http://cals.arizona.edu/waterquality/EducationalResourcePages/OnsiteWasteManagement.htm