The ruling party in Uruguay seems likely to act, according to press reports: “If approved, Uruguay’s national government would be the first in the world to directly sell marijuana to its citizens. Some local governments do so[?].” http://www.telegraph.co.uk/news/worldnews/southamerica/uruguay/9346047/Uruguay-government-announces-plan-to-sell-marijuana.html
A monopoly provides the advantage (over taxes) of instantaneous price adjustments that can accelerate the death of the black market. I figured the first country to get into the business would be a tiny island country whose tax haven business the developed countries had shut down, but who knows?