I bought this Knolly with 27,5" Pike already installed but with both 26" wheels. This bike just rides better with 27,5" in front comparing to original 26". HA is slacker and bike picks up momentum more easily in rough stuff. And yes, I have no problem buying Schwalbe Evo tires in 26".
Making 27,5"/26" mullet can bring a new life to an old sled when you cannot buy new one. That's all.