Summary

11/11/17: Updated cap to fit tighter.
11/29/17: Tighter switch space, longer arm thing.

This is really just a visual copy. I think the original uses a miniature snap action roller, and this is a sub-miniature (13x5x10mm) like the one in the original i3 Mega sensor. Below is where I ordered it. The connector was removed, pins bent up (at the board level) and soldered directly to the switch (S and G, V is not connected). The bearing was actually broken and didn't turn, possibly when the PTFE tubes used as size adapters took a ride on the filament, so there's the problem.

https://www.ebay.com/itm/3-Pin-1NO-1NC-Subminiature-Micro-Switch-W-Lever-Roller-5pcs-S7P7/172667598181?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649