Seeing that Proof has one dedicated line for what I think is the 6.5-PRC Savage is my guess. Now, consider all the other offerings from Proof in every length, caliber and contour. Those are short runs and $700 approx. If all the rifle manufacturers offered generally the same barrels then I think that market would be mainstream or close to it.
For general observation, I know one guy with a CF barreled gun. It is the Savage 6.5. Just got it. When I look around, no one else in my large circle has CF anything. Not because they're bad; they just don't see the need apparently. They don't even discuss it.