According to John Jeavon's research. A vegan can feed themselves on 4000 SF of cultivated earth. There is 43,560SF in an acre. Even with a 2 foot path between the rows it would come to a total of 5600SF. That is 5 beds of 4'by200'. An acre being nearly 210'x210'. This is both a large area and a small area in how you approach it.
If we designed out cities to where all houses were placed on the very northern edge of our city plot, we would have ample southern exposure for everyone of us to grow most of our food.
I am currently thinking of where to find an acre dirt cheap so I can build my tiny solar house with rain water catchment.
The nice bit is, while I have no idea what the actual cost involved is for the land.... I am happy to see that you don't actually need an acre to sustain yourself on.
With a plot 80 feet by 200 (A 1/3 acre) you could have your two story 20x40 foot (1600SF) home and your personal farm. Along with enough extra space to leave wild growing a cover crop like alfalfa to produce enough compost. :) If you did manage to get your acre then you would have a huge plot of wild green to compost.
So many thoughts. Now to find money to do it.