Have you considered getting some quality half chaps instead of tall boots? I have a pair of Tredsteps (www.smartpakequine.com
) that are smooth leather and fit perfectly. Instead of just choosing "s, m, l,", etc you pick exactly your height and width combination! My size is a 14/17. I buy them an inch longer then I need because they do fall about an inch as they break in.
If you really need tall boots you could look into customs, but they're going to run around $800 or so! (for the basic cheaper models)
Or... my tall boots were a little too snug when I bought them so I took them to a shoe repair place and got them "stretched". (no, does not affect the look or structure of your boots in any way) It's only like, maybe1/4 in? But it was only like, $20. And now they only need a "firm tug" to slip on and don't cut of the circulation to my feet!