Kohldad , with all due respect your last sentence was a bit condescending .
To the topic , yes off roader's have been airing down for a long time . Because of there light weight most off road vehicles have tires that are 2 or 3 times under their load capacity so the subject becomes moot . On a heavily loaded truck with camper where the tires are almost at capacity to begin with it becomes a concern , at least for me . The charts from Firestone and Michelin are for LOW speed not for highway speed , yet they make no mention of low pressure and low speed . I am aware of all of the things you mentioned and I don't need a chart to make me feel comfortable , however I do need more than opinion. I was simply asking if anyone had found supportive data .
http://www.bridgestonetrucktires.com/us_eng/real/magazines/98v3issue4/v3i4Tech.asp