Freeman editor Sheldon Richman has published a sympathetic overview of left-libertarianism in The American Conservative. (Yes, a magazine with the word "conservative" in its name has run an article celebrating the fusion of two alternatives to conservatism. The political spectrum isn't as linear as it sometimes seems.) This isn't the "liberaltarianism" of Brink Lindsey and Will Wilkinson; it's both further left and more anti-statist than that. It isn't the collectivist anarchism of Bakunin either (though that's been praised in The American Conservative too), or the "left-libertarian" Lockeanism of Michael Otsuka. It's these guys:
These passages—the first by independent scholar Kevin Carson, the second by Auburn University philosophy professor Roderick Long—read as though they come not from libertarians but from radical leftists, even Marxists. That conclusion would be only half wrong: these words were written by pro-free-market left-libertarians. (The preferred term for their economic ideal is “freed market,” coined by William Gillis.)
These authors—and a growing group of colleagues—see themselves as both libertarians and leftists. They are standard libertarians in that they believe in the moral legitimacy of private ownership and free exchange and oppose all government interference in personal and economic affairs—a groundless, pernicious dichotomy. Yet they are leftists in that they share traditional left-wing concerns, about exploitation and inequality for example, that are largely ignored, if not dismissed, by other libertarians. Left-libertarians favor worker solidarity vis-à-vis bosses, support poor people’s squatting on government or abandoned property, and prefer that corporate privileges be repealed before the regulatory restrictions on how those privileges may be exercised. They see Walmart as a symbol of corporate favoritism—supported by highway subsidies and eminent domain—view the fictive personhood of the limited-liability corporation with suspicion, and doubt that Third World sweatshops would be the "best alternative" in the absence of government manipulation.