Krishni, those are cute, though a little more casual than what I have my heart set on, and also I really want cognac not brown (I already have brown & wine boots - years and years old but still in good shape & classic).
Betty, it may not be a factor of overall height. It may be that my lower leg is proportionately short. I dunno. But also my calf is narrow - 13 inches. Proportionate to my height it's not narrow, it's rather average. However this ups the challenge since narrow calf boots are rare these days too. I am sure it's even worse for someone who's long legged AND narrow calved.
I think Frye's got the right idea in that it seems that the shaft height & circumference is adjusted proportionately to the shoe size, so the size 6 shaft fits me perfectly whereas the 6.5 is about... 1/4-1/2 inch too tall and too wide. If only my foot was narrow and not so full. It's strange because I rarely, if ever, need to go up to a 6.5. Just this brand. It feels more like a 5.5 on my foot.
If you go into Zappos and do a search on 13 x 13 boots, you wind up with only cowboy boots. I guess I need to move to the South!
In the past I had way better luck. I do own tall boots, but none that are newer than 6 or 7 years old (not counting cowboy boots). Something shifted. We saw the emergence of "extended calves" and that's when I stopped having luck, despite searching every year. I think manufacturers wised up that people are getting taller.