RE: PAIN IN THE A$$ RUBBER BOOTS!!!
Try this link to Cabela's. They aren't zippered, but they do have the clasp to allow for larger calves or tucking in your pants. However, my guess is that you're having trouble getting your foot squeezed past the tight ankles that the new rubber boots have. I'm only average sized, with 9 1/2 M feet, and I have trouble with them as well, but not as much as you're having.