Has anyone ever seen one?
Herb
Jay has one as expected
http://www.mtfca.com/discus/messages/118802/119472.html
Stan Howe shows his NOS Ecco timer of similar design in this thread: http://www.mtfca.com/discus/messages/257047/266051.html?1328807001
I believe the key factor is to make sure the current does not actually flow through the bearing balls. The ECCO appears to have this dealt with.