In reply to ben1234:
Firstly, why does the chainset need replacing - I assume it's just worn out?
Otherwise, I'd tend to agree with Beardy Mike.
Bottom bracket is easy enough to replace and putting a single narrow-wide ring on triple XT cranks seems a common enough tactic.
Regardless of if you change your rear wheel/hub, you'll still need an 11-speed rear mech and shifter.
Depending on what shifters you've currently got, you may also need new brake lever(s).