Naphtha is a vague class of petroleum distilates. Some sources list gasoline and kerosene are Naphthas.
http://en.wikipedia.org/wiki/Naphtha

White gas(Coleman fuel, Shellite) is the form we can get and would be interested in. It does have a low flashpoint and relatively low boiling point. Autoigntion temp is hard to find, but one listing I found put it at 321C.

I too think that a low percentage ether mix may be the final outcome of our experiments. 5% is low enough that it's cheap.