There are only a few flavorings that I use for my pipe tobacco. I don't use flavorings that come from food sources, such as fruits, chocolate, coffee, vanilla, rum, etc. The aroma given off from the tobacco and the fragrance coming from the food flavoring agent don't seem to pair well with me. There are some essences that, in small amounts, do compliment tobacco well. I have 3 working blends below.
1 My favorite example is to make a blend of cigar leaf and Burley. I then add just a very, very small quantity of cedar extract - just enough to let you know it's there. The cedar and cigar leaf pair well with each other along with the full-flavor nuttiness from the Burley. This make for a stout blend.
2 Another good blend I make is to use lemon Virginia, Burley, Fire-Cured and a very small amount of juniper berry extract. A great outdoor Michigan smoke.
3 Also, Burley, Izmir, Tambolaka, and a hint of Frankincense. This is my most bizarre blend. The Burley and Izmir make an interesting base. A moderate portion of Tambolaka is used and pairs well with a trace amount of Frankincense. This definitely not for the lighthearted smoker. I don't smoke this much, but I do find myself getting a craving for the Tambolaka/Frankincense aroma.
These are my only pipe tobacco blends to which I have added flavorings. I found the key to the success of these blends is to use the very smallest amount of flavoring - so little that it is difficult to detect. It is easy to over do it and that will spoil the smoke. I want the tobacco aroma to dominate and to be at the forefront of the smoke at all times but with an occasional hint of fragrance. The above extracts are strong so a little goes a long way.
Before joining the FTT forum, I used to blend my pipe tobacco by purchasing what is referred to as "blending tobaccos" from online vendors. This was the only way to blend tobaccos until I learned about the infinite possibilities of blending tobaccos when I joined FTT. So the above blends were made with these blending tobaccos. I would like to revisit these blends with my own grown tobaccos or tobaccos from Whole Leaf Tobacco.com. I can only imagine how the difference in quality and aroma will manifest itself.