Just thought I'd toss of few of my cents into the discussion...
First: Being this is a discussion on Legislation Circumvention, we need to really look at the roots of the laws we seek to bypass - Ie: What is the Legal definition of Tobacco?
We likely are all well familiar with the relatively new 2009 TCA wording: "Tobacco Products are anything including, made from, or derived from tobacco" . . . This is new wording, and relatively untested. The ATF (TTB) still uses the IRS definitions of Tobacco Products which use the wording "Made of or including at least 50% Tobacco". This is why the ATF (TTB) doesn't care about e-cigs. It's the distinction "derived from" creates...
...and for right now, it is that distinction which is allowing our beloved cottage industry to thrive, and lets us ship our E-cigs accross state lines without state by state stamps...
So we're talking about here, as with all legal and legislation topics, is matters of extremely precise definitions...
So, for this concept to work (non-tobacco based nicotine going unregulated) - we need to understand the specific definitions of 'Derived From' and 'tobacco' . . . Mind you, we aren't looking for common or agreed upon definitions, we are looking for are the ultra-specific legal definitions of these terms. For example: If the legislators want to define anything that is Solanaceae as Tobacco, they can do that, and then they use selective enforcement to skip tomatoes and eggplants.
First, "Derived From" - This is where they get you coming and going. 'Derived from' has no formal definition. Common sense says it means 'Directly or in part a product or reduction of an existing thing'. But legally, that's not exactly what it means - the legal definition can be coaxed to mean: "Inspired By". . . Now, that may seem silly, but that doesn't stop it from being true. Synthetic Nicotine that has no link to tobacco can be considered 'derived from tobacco' insomuch as it is 'inspired by the simulation of tobacco' . . . Most good judges wouldn't allow that, but the law is vague enough in this area that I wouldn't place my stock in the synthetic nicotine argument and hope for it to hold up under regulatory politics...
So next is, Tobacco: Family - Solanaceae, Genus - Nicotiana. It is not technically tobacco which is regulated, it is in fact anything in the Genus Nicotiana. Or anything derived from anything in the genus Nicotiana.
So, synthetic is a possibility, but it's cost prohibitive, ineffective, and in practice some clever bureaucrat will change the wording from 'Synthetic Nicotine' to 'Synthetic Tobacco' and the open up the floodgates of the 'derived from argument' (a synthetic can be said to be 'derived from' it's original even if it has not physical link to the original). . .
Eggplants, tomatoes, and Potatoes are also cost prohibitive and essentially impractical to even consider...
But there is a hopeful from down under: Duboisia Hopwoodii a shrub from Australia can be grown in many climates, has as much or greater nicotine density per square acre as the Nicotiana's, is a Solanceae, is not a Nicotiana, has a very similar alkoloid profile to tobacco, and can be extracted without first curing... It's cheap, hearty, grows like a shrubb, and puts out a formidable amount of nicotine that in some varieties and at some seasons can be greater per leaf than tobacco...
So why aren't we already seeing Duboisia hopwoodii everywhere? Why don't we already smoke it? Well, for one, it's a shrubb, it doesn't lend itself to curing the way the long leafs of tobacco do, so when smoked it is harsh.
Second: It doesn't have the rich flavor taste of cured tobacco. Third: It has hyoscyamine in it's alkoloid profile. Not a huge amount, but if harvested incorrectly (wrong time of year) you can get pretty big (full on hallucinatory levels) of hyoscyamine.
So what is hyoscyamine? Well, not nearly as reactive as Scopalomine, it is pretty similar in it's effects, which can at high levels include: dry mouth and throat, eye pain, blurred vision, restlessness, dizziness, arrhythmia, flushing, faintness, cause headache, nausea, vomiting, and central nervous system symptoms including disorientation, hallucinations, euphoria, sexual arousal, short-term memory loss, and possible coma in extreme cases. Some people can experience transient combativeness.
Personally, none of those really bother me, they are all a lot better than throat cancer as I'm concerned...
But if one of you clever O-chemists can distill out the hyoscamine, the rest of us can enjoy a totally organic source of none Nicotianic Nicotine that will basically bypass all this current round of legislation... Convince some farmers to grow it stateside, create some jobs, and viola! You'll have revolutionized the world of vaping...