Some that have suggested this are Ahlusion and, specifically, Wlad. Taken from the site:
Non Aromatic Blends: These also contain extracts of additive free natural or certified organic tobacco, but may also contain commercially available tobacco flavoring.
I won't post any info directly from Wlad, though I have spoken to him about this very thing, and I can say that it's just a long version of that statement.
I taste straight-up synthetic tobacco flavoring in many of the non-aros along with, as Wlad puts it, authentic "tobacco notes" -- but it really matters not. They taste good in spite of their synthetic flavorings. I do think the House Blends (or at least HB by itself) doesn't have any added synthetic tobacco, but that's because I hardly taste anything to begin with, let alone a synthetic note. I will say though that since I've been DIYing, I see that the ONLY thing that really matters with regard to natural vs. artificial is the end taste -- I'll take a 100% artificially flavored liquid that tastes great over a 100% natural product that tastes like yuck mouth!
I've tasted more than my share of yuck mouth from other vendors. Beware the .... Sauce!

