Aaaaaaand that's that!
We've got 5 entries, 4 people, 3 designs, 2*2 balls and one winner, namely:
MrDo!
Second comes in markman
and the third place goes to Njaa.
Where markman and Njaa took the proven route of a pulley system, MrDo saw an oppertunity to do something revolutionary, which could only be pulled off with the reduced-size armadillos, giving him an advantage of over 150 dollars over the second place.
I'll hold you back no more, here's a screenshot of the cheapest solution:
Since MrDo wasn't sure if his cheapest version was light (the metal at the top is pushed up at the start), he made a second version. In both cases, he takes the grand prize! Congratulations!