Area Banker. I imagine there is far better Area than this possible, as this is more of a Cycles solve, but this is more expensive than another solve I made with lower Gold. If Biggie uploads something with lower Area than 19 that will usurp this solve!

Also, judging by weekly forum comments, I bet this is pretty close to what the guy who claims to have made a solve purely with tools has. They gave away that they used 3 pistons & 3 calcifiers with a total cost of 210 Gold, though they said their track loop was 19 whereas this is 12, so this probably beats theirs unless they have improved!