Here's a 2010 youtube interview with Peter McDermott, who started his urban farm in Cleveland using SPIN (and he also notes other influences including Coleman and permaculture). I attended at tour of his place around that time, and they were selling into farmers markets.
When SPIN first came out, I bought the PDFs. Basically they teach you how to get a lot of yield out of a small space by growing things in succession and growing varieties that produce in relatively short time frame (so you can get successive crops). They also show you how, if you lack land of your own, you can approach neighbors or landholders and essentially farm their properties.
It's interesting information and something that Stacey Murphy is doing as well. Is it permaculture? Not specifically - but it could be made to be more "permaculturish" with the addition of water harvesting elements, trees, nitrogen fixing plants, pollinator forage areas, etc.
For me, the information was interesting but not all that useful due to my climate. We tend not to use raised beds in the desert due to the fact that they waste precious water. Also, it takes on average about 3 years for us to build decent "veggie garden" soil. While I've spent the time to set up water harvesting, sunken beds and soil building on my own property, it's a lot of work. I doubt that I would want to invest all that effort on someone else's property for very little yield for several years. Plus, I grow stuff under the shade of trees - which need to mature. Otherwise I need shade cloth during certain seasons. I will also always need to rely on some form of irrigation during most of the year.
Subtropical desert (Köppen: BWh)
Elevation: 1090 ft Annual rainfall: 7"
I have read through some of "booklets " as they are called. As other's have mentioned, nothing real new.
Plan is to keep food close ti where it is consumed, mainly using other's land, in exchange for veggies etc..
It's not new, but a great idea. The farming info is mediocre compared to other books. As i mrntioned the primary purpose of the books is to make money for the folks selling them. Something that is way to common.
Location: NE Ohio (Zone 6a, on the cusp of 6b) 38.7" annual precip
I think Diego and Curtis did a good job talking about it. While this isn't "permaculture", it is a tool to get farmers land access, increase the consumption of healthy food, and spread the interest in localized food.
I think that you will probably have to keep it basic and follow the SPIN methods if your new or the land owner is iffy about the idea, but you certainly can diversify and "permaculturize" your strategy to optimize diversity, soil creation, no till practices, etc...
Seems like a great way to build a "portfolio" and diversify your income stream.
I will suppress my every urge. But not this shameless plug: