Nice one Jacques, looks pretty cool.
For us slightly shorter blokes it's not an option, but I do agree with you even at 5'10" my knees are pretty bent when riding. I can just imagine how you would feel.
One disadvantage of the standard seat I found is that when you try to sit a bit further back against the ridge, you tend to slide forward, pulling your crotch in and sort of pinching your ..... you know what I mean. With a flatter seat that is reduced or eliminated.

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2014 XT660Z - Barrett pipe, DNA stage1.5, Barkbuster hand guards and handlebars, Pivot pegs, Teknik suspension, Guard-it engine protector combo, B&B rear rack, Trax topbox.