It's easy to discuss the feasibility or impossibility of local, small-scale sustainable horticulture or permaculture, vernacular architecture, and low-consumption, high-quality-of-life-living. These people aren't just talking--they're doing and they're sharing their adventure (and what they've learned) with the rest of us. This is truly critical if we are to leverage our "one time shot" (of the availability of unsustainable, high-tech communication) to develop a truly sustainable, high-quality-of-life culture:
Ran Prieur: Ran is developing a permaculture homestead on a few acres in rural Washington, complete with plans for a cob cottage.
Lichenology: Zane is building a sustainable homestead in rural British Columbia.
Farmlet: Kevin & Rebecca are building a permaculture settlement in New Zealand
Farmer Scrub: Norris is building an urban permaculture oasis on a standard house lot in Portland, Oregon.
Please post other examples of this kind of ideologically-focused experimentation in creating self sufficiency in the comments--I plan to provide some of my personal plans on this topic soon.
On another note, take a look at this excellent essay from Rob at Transition Culture about "The Tuscan Way of Surviving Collapse." It's something that is near to my heart--I've written about future sustainability modeled after the Tuscan system--and it is valuable as a bridge between the kind of personal examples of the "practitioners" listed above with creating a fully sustainable society.