My closest approximations would be ones that include my flue cured cavendish which is made by the pressure cooker method, with 2% glycerin by weight (during the cooking), and whisky equal weight to the tobacco after the cooking, (which was only added to stop mold).
This is then used as a blending component, maybe 33%-50% in a blend. Alcohol based vanilla narrows it into the aromatic category and various flavourings in small amounts just to tweak.
The glycerin adds an I don't know what which really brings it into the commercial aromatic vibe.