ah mekugi, i couldn't get the word menuki out of my head lol.
there are some modern bladed that use metal pegs of some-times nuts and bolts. i've always wondered wether the difference between metal and bamboo was just a traditionalist standing or actual fact. i'd try and find out personally but my mum doesn't want me to have/own any bladed weapons, specially 3 foot ones lol - i'm easing her round to the idea.
Go seek the advise of a qualified instructor.