4.5 ft * 10 billion  = 45 billion feet ( of raw material)
^ Avg ht.     ^ # dead people
considering
feet on 
shoulders of 
the other person


45 billion feet = 13 716 000 000 meters = 13 716 000 kms

Distance of the moon from earth is 384 403 kms (wikipedia)

So, number of possible ladders constructed of human dead bodies from earth to moon in 100 years = 13716000/384403 = 35.66