I must be built funny.

[OakLeaf]

I'm also wondering what the issue with your knees might be.

It's true that only the smallest complete bikes come with cranks shorter than 170mm, but that's a crank swap, not a frame issue (and it's a swap I had to do on my 50cm C'dale).

If you're having trouble finding a frame with a short enough TT, but seat-wise you can fit on a larger frame, consider just buying a smaller frame and an uncut fork. Then you can set the handlebars and seat where you want them in relation to each other. Not the most inexpensive thing in the world but a whole lot cheaper than a custom frame!

If you're more specific about your proportions I bet there's someone here who can suggest a frame for you.