Well, I ran across an article in the Dec 2014 issue of Piper Flyer magazine titled: "Restoration on a Budget: Senaca Power Control Panel Upgrade". Part of the project was replacing all the rocker switches. The mounting of the Senaca switches are slightly different than the Twinco. They use mounting tabs held by screws, whereas ours are a plastic snap in.
Anyway, the switches were obtained from a company called Chaparral Parts. Their new website is
www.chaparralparts.aero, and their phone is 866-865-1262. I went to their site, and the switches range from $46 up to $79. Too rich for my blood.
I think a better way is to change to bat handle toggle switches (in the $15 range, from Aircraft Spruce), and mount them in their own panel to the left of the pilot control yoke. Labels can be put right on the panel, and everything is right up there where it can be seen. No more feeling around by your knees for the right switch.