Lots "looking", very few "find".
Still possible for your gunsmith to buy a factory/new 35 Whelen barrel from Remington and fit to a 7600 30-06 or 270 "donor" gun.
I won't sell the Whelen pump I have either, but a couple of locals have gone the re-barrel route quite happily. It's about a $ 350 - $ 400 touch, but at least " you gets what you wants " !