These days, my calves are the size of most mens' thighs. I now wear 42" Sears "Canyon River Blues" (comfort cut), and they give me plenty of room for OWB and IWB.
Like I said, jeans vary. You have to find the ones that fit, not the ones someone else wears.
As for the thighs... must be a freak genetic thing. I'm not a muscle man. I don't lift weights. But you don't want to get into a squat contest with me; I leg-pressed 750 on a Universal gym in high school, when I weighed about 140.
Kevin