Here's a link about it http://nvinc.com/allodial_title_in_nevada.htm
It used to be a means to pay a lump sum in advance and not pay yearly taxes. I understand it was discontinued. It is very very rare and I personally have never dealt withit in the 36 years that I have been selling real estate.
RE/MAX Realty Affiliates
1320 Hwy 395
Gardnerville, NV 89410