Inspired by this question, I want to ask if there are any existing beer flavored using tobacco or have a hint of tobacco in the taste.
If used the the brewing process, the nicotine in the tobacco leaves would be extracted into the beer. Too high a nicotine dose in the beer would be poisonous. The whole process would probably be more effort than it is worth.
As for tobacco flavor, it depends on the flavors that you enjoy in tobacco. Just like some smokey whiskeys work well with cigars, some rich beers work just as well. Strong beers aged in spirit barrels often contain the same oakey, vanilla notes that are present in the aged spirits. Cigar City Brewing uses a lot of different barrels to impart tobacco like flavors in its beers and their tasting notes usually suggest pairing a beer with a cigar.
If you are looking for a smokey beer without the possibility of nicotine poisoning, then I suggest Rauchbier. Some of the malt used in this beer are smoked over different woods (usually alder). Some breweries experiment with adding smoked malt to other beer styles (Porter,IPA, etc.)
There are indeed several kinds of liquor, beverage and food flavourings available on the market, being "smoke", "barley" and "tobacco" just a few of them, found in niche stores throughout the whole planet and not a bit hard to find - and this may be the answer to all interested brewers out in the wild.
I used to know a particular aquaintance who enjoyed for instance, to drop a whole chopped and minced chewing tobacco tablet from a notorious retail brand, into his beer can or bottle, before chilling it, and letting it age for a few days or months.
Later, I learned this was rather a widespread and not-out-of-the-ordinary habit, and thay he had become a brewer himself, and kept doing that and selling the product, with relevant success.
I just tried some of one of its products, which flavor could be described as a "spicy, woody-smoke-flavored-with-some-murky-notes" stout ale, quite enjoyable, by the way.
Cheers, and keep on the good brewing.