Thanks to @colesonchildfor the design inspiration and @rpower1401 for the drive mechanism idea. Both came together to allow me to build something that had been just out of reach for a while.
This is my take on the guillotine treadle hammer. The main ingredients were some RR track, some receiver and hitch tube, and some I beam racking from a box store.
Sorry I didn't show any action shots, kind of difficult when using a cell phone to record. I will see about getting some shots of it in use soon. But trust me when I say that this unit HITS!