Interesting article indeed, and the chemistry appears legit. Although I'm far from being proficient in chemistry myself, it looks like a fairly simple equation.
In any case, I think "freebase nicotine" is simply too fucking deadly to market. As mentioned the OD dose is ridiculously low, and I really doubt the "rush" would be any more desirable than sniffing glue.
IMHO, you'd have to be one desperate cigarette junky to stop buying the real stuff in favour of "freebase nicotine"....
--- G.