We have been kinda kickin' this one around in the "building a pier" thread. Jeff Gaines used concrete piers and set cedar 6 x 6 posts. I started my thinking with setting 6 x 6 treated posts into a post hole at the bottom and filling 'er with concrete...but...I am re-thinking (as I so often do). A major concern is horizontal shear and wracking from not only wind but much more importantly: shifting ice. I really like Jeff's idea of a poured concrete pier at the bottom and then set the post "on top" in a some kinda stainless of galv mounting bracket. To address shear and wracking of the structure above, you would add substantial cross bracing like the old railroad trestles. As of this posting, this is where my little engineering brain is headed. This is basically how I constructed an octagonal gazebo in my backyard...by setting the posts "on top" of the concrete piers. I have a western exposure that is flat and goes forever; it has withstood some killer winds with no wracking issues due to cross braces (4 x 4 ex's) between the 8 corner posts.