This suburban apple farmer is a great example that, while it may remain impracticable for many people to achieve true food self-sufficiency at their present property, it is certainly possible for most people to take significant steps in that direction. Just a few more examples of people who are working on this transition as we speak: Farmlet (of Cryptogon fame), Mossback Farm, and Lichenology. I've also written about The Self-Sufficient Gourmand.

These examples don't specifically address the economic efficiency issue per se, but I think they do highlight that the ultimate goal of economic efficiency is to fulfill human needs--these people are all very bright and could easily be making six figures elsewhere if that was their sole desire. Instead, they seem to have realized that small-scale farming, while perhaps earning less money, fulfills their true needs far better than pure monetary analysis would suggest.

And while these gardens can absorb a bit of time, clever gardening practices (i.e., mulching, companion planting, etc) can greatly reduce the amount of time spent weeding, which is arguably the most time spent in the traditional home garden. And you'll be surprised how much you can squeeze in a yard;

I have a full time high tech job, though have a flock of 20 sheep, 45 fruit and nut trees in an edible landscape, and 18 raised beds (3'x12') in my home garden. While I obviously have more than a 1/4 acre, it shows that this does not have to be a full time job by any stretch of the imagination. It does get busy at spring planting time (or lambing time) but it is a fulfilling busy-ness that gives one a feeling of satisfaction and a sense of accomplishment. And the grocery bills are much, much lower than they used to be.

Even people living in apartments (with somewhat south-facing balconies) can grow some of their own food;

Looks like I'm a little late to the party, but thanks for the kind words, Jeff. Being mentioned in the same sentence as Kevin (farmlet) and Zane (lichenology)...I just hope I can live up to the expectations.

Keep up the good work