Seems like a crap shoot to me. First of all, it's pretty difficult to guess what cigars are going to be in demand in 10-15 years from now. Furthermore, storing cigars for that long in the proper conditions, and maintaining the necessary records takes a fair bit of work. Plus it's pretty hard to predict what is going to happen in the cigar market that far down the road - for example if the embargo is lifted and the Cubans ramp up production steadily the value may in fact go down, not up.
I can think of easier and safer ways to make money, albeit they may not be as tempting or enjoyable.
If you were to put down a few boxes of good cigars for your own enjoyment, and then discovered they were worth substantially more than what you paid for them, that would be one thing. However, if you're putting a lot boxes down specifically to try to make a killing on auction you may be rather disappointed.