>> I plan on filling the beds with compost and topdressing with buffalo and camel manure.
I may be crazy, but I'm wondering if that might be TOO rich and organic. It would continue to decompose through the growing season and tend to subside so that the bed would lose depth each year.
I would be inclined to use no more than 50-75% compost plus manure, and make up the rest with screened soil, especially if I could find some sandy soil or even gritty sub-soil. I like my soil to have some grit for structure, to keep it "open" so water can drain out and air can diffuse in through open pores and channels.
Then I would top-dress or turn under 2-4"of compost and manure every year, or as much as would fit into the bed without overflowing.
It's cheap and easy to make 16" high walls with concrete paving stones stood on end, but 2-3 rows of cinder blocks are more stable and you'll never have to 'straighten them up".
I once saw concrete pavers that were 24" x 24", and lusted to make a REALLY deep raised bed, but didn't think I could get them home unbroken. or lift them unassisted! Probably really deep beds need wooden walls, even though that's more expensive and they don't last forever.
But if you have have hard clay soil, the idea of berms for raised bed walls might be perfect.
Just allow for drainage under the berm so you don't make a mud wallow! A slit trench filled with gravel and covered with filter cloth (under the berm and leading down-slope) is probably plenty, but this corrugated, perforated drainage pipe is very cheap and much lighter to carry than drainage gravel!
