I wouldn't be surprised if you can grow the seed head indoors until it ripens. Think cut flowers, cut the seed head and shove it a pot with some potting mix. It might not root, but tobacco is stubborn enough to live until some seeds mature.
i don't know about potting mix but you could certainly try a bucket with a little bit of water in it.
below in an excerpt from an article that talks about getting seed out of non-ripe capsules to germinate. however, I don't know how well this seed would STORE as opposed to germinating it immediately, and therefor I DO NOT recommend doing this to all of your capsules if you happen to lose your seed head. it would make for an interesting experiment tho to see about the longterm viability of seed treated in this manner.
in that same paper that talks about the 2% bleach and acetone method for breaking seed dormancy, it also says: "Dormancy in N. tabacum rarely presents a problem. Tobacco seeds usually germinate reasonably well as soon as the seed capsule has turned brown and the seeds have fallen of the carpels (I called them the placenta somewhere else). A period of seed dormancy exists however between the time seeds reach their full size and when they have turned brown and are free of the carpels. This period may vary between 1 and 3 weeks, depending on growing conditions. Seed produced in the greenhouse during the winter months will tend to mature over a longer period of time. The N. tabacum indicated in Table 1 (Germination: 0% untreated vs 92% treated) was obtained by scraping seeds, which had begun to turn brown, from the carpels of a (green) seed capsule of the variety Vamorr 50. Although this method was used for comparative purposes (the main study is about breaking seed dormancy in a couple Nicotiana species), it illustrates a method whereby seed of N. tabacum can be harvested and forced to germinate several weeks earlier than normal." (Burk LG. 1957. Agronomy Journal 49:461)
