Two commercial possibilities. I had the Eldico EE-3A and this one has a
sloping front and was quite common. An even older keyer that used bigger
tubes was the Mon-Key. I had one of these in the late 50's. These were
made between 1947 and 1954. On this one you can hear relays clicking as you
key it (above the built in sidetone). I have a schematic somewhere and will
look for it.

Dave K4JRB