I was kind of wondering the same thing since knee boots have come back in style, but I'm also seeing them everywhere in the media (not so much where I live.)
I searched everywhere for a pair to fit my skinny legs and found a pair a few years ago.. I find them uncomfortable in the knee area...that's where my skinny jeans bug me too #sensitiveknees? lol.
But I did score some Sam Edelman knee boots (the perfect height right below my knee cap) in red mock crock last night at the Rack for $79. They have a pretty high heel but they're great sitting boots and I've been wanting to add a little red in my wardrobe. Oddly I can't find them online or I'd post a link.
I was really excited at first bc they were in a Stuart Weitzman box, but they're pretty comfy in spite of my feet really liking SW. (wallet does not, lol!)