Well the leaf wouldn't technically be tobacco when it arrived, you'd charge me for the service of essentially arranging my property, and it's legal to ship cigars thru the post, you wouldn't be selling me anything, I already own it. The same if you rolled some for me using my leaf at your house if I happened to visit.
But as Bob says, it's still probably illegal. Somehow. Although I suspect that it's sufficiently gray that it wouldn't matter unless you started making enough money to attract the parasite class.