so how about instead of an arm, you do a escaltor type deallie, have a concave tetra style figure at the base of your bot and then with like a couple of belts drive it up and deposite on top, we had something like that last year except it went the opposit way. i dont see why that wouldnt work
^/|
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^/__| kinda sorta
you get the idea, im trying to think outside the box