Have you read about the Loma Linda Adventists? I'm curious as to your opinion. It's epidemiological of course, but very interesting and well done.
I just find it interesting that they avoid meat (mostly) and eat lots of nuts, yet have very good health by any standard. (Not just compared to SAD.) They have no problems with grains or PUFAs. (Avocados, nuts, veggie oils...etc) They have extremely low rates of diabetes. If PUFAs are the cause, as you say, then they shouldn't have high levels of protection.
My theory is that PUFAs are horrid when not in it's natural form. Raw nuts, avocados, fish...they all seem to correlate with good health. (Yes, correlation =/= causation). It's just when we extract PUFAs and over-process them that they cause their severe damage. For instance, corn oil seems to be one of the worst things you can put in your body...and it is virtually impossible to get in nature...it requires vast processing. I simply can't find it in me to fear PUFAs in natural form. (Though I agree on your opinion about transportation....here in Texas even raw nuts have likely sat in 150 degree trailers for extended amounts of time. That probably isn't good.)