Isn't it the case that Boeing are now using composites for more and more of their aircraft?It needs to be used with respect for it's properties and can be added to comparatively easily if more stiffness is needed.

It is a little monotonous reading accounts of the planning of machines intended for wood,plastics,alloy -oh and maybe some steel too.The whole forum is littered with those and really it would make more sense to buy a new Haas or retrofit a Bridgeport (or clone) if steel is likely to figure in future plans.