With the custom work on the lifter ejector, etc., a new 336 in 35Rem will be cheaper. Mic McPherson at
www.levergun.com/ has an article on what is attainable on the Marlin action. The 357 Win 94 action would be a cheaper route, but it has some issues for feeding reliably. Incidently, I have no relationship with Mic and his wife is not in very good health, so you may have a wait.