Bill,
Here in Texas there is a condition used to gain control of property such as you have described. It is called Adverse Possession, not Eminent Domain.
Adverse Possession is defined as - a method of aquiring title by possession under certain conditions. Generally, possession must be actual, under claim of right, open, continuous, notorious, exclusive, and hostile(knowingly against the rights of the owner). Exact time (years) of the possession and specific requirments (such as payment of property taxes) vary with the statutes of each state.
More than likely, some type of legal action to obtain clear title is occuring. Any effort on your part to improve and lease a property you do not own would be at least unwise and at worst fraudulent (criminal?). Whoever owns it would be under no obligation to sell it to you. If you have obtained your information as to who has been paying taxes/ownership from a public database CAD online, I would venture to say that we find those types of records to be very inaccure quite often. I run accross CAD errors constantly. Sometimes it looks like these people input information incorrectly on purpose. So if BOA says they don't own it, they very well may not. If the taxes are up to date, it has not fallen through a crack. Check the adverse possession statute in Nevada. Stick a sign in the front yard that says you own it and see what happens. People here have done this before and gotten away with it (according to one of my instructors).