I have black walnut trees that may be a little over half that size at the back of my property. I don't go under them on a windy day when the nuts are ripe. I had to laugh at just the thought of trying to 'pick' them - that truly would be nuts. But, it got me thinking... You might be able to get most of them off - How 'bout if you tied several ropes up into the tree (when there are no nuts on it) and used them to shake it at your convienience for a 'controlled drop'? Would take some work initially. Otherwise I'd say fire up the chainsaws. Whatever can't be sold for lumber makes good firewood.
i have tried to give them away in boxes, told people to come over and take what they want, and i just cant seem to give them away! lol! i cant just pick them either... the tree has to be close to 100' tall and spans out my entire back yard.