The web site above shows this tool which we have been manufacturing for going on 20 years---it will allow the operator to increase instep height by up to 8mm
which is usually enough for most high instep folks.
We have sold them into numerous shops and will also stretch boots for folks who send them in. We charge $50.00 plus shipping to stretch a pair of boots. I have looked, and so far we have not
sold any into your neck of the woods, although we did sell one to Green Mountain Orthotics Lab at Stratton Mountain VT. see Bill Haight.
My thought here was to show that even if you can't find a boot that will work out of the box, your instep problem can be addressed.
Boot fitter recommendations: Mud Sweat and Gears in Ellicotteville, NY., about 5 hrs drive for you, or Bill Haight 6+ hrs away---as you said boot fitters are hard to find so a drive might be in order.
Edited by miketsc - 10/6/15 at 1:23pm