I have spoken to Dennis Murfin who's bike featured in the magazine mentioned at the start of this thread, below is the reply from his email.
German models were fitted with indicators when new so RH switches incorporating the starter push button and the two way winker switch are, or were a standard part.
Up until a few years ago they occasionally came up in the US on E-Bay but always fetched silly money, at least more than I was prepared to pay.
The ones I have on my bikes are 'home made' using bits of other switches but both based on a SL90 kill switch which are still available. By a stroke of good luck I found that the SL90 uses the same basic casting as the German market CB72/77 winker / starter item
The conversion for the CL was easy, the kill switch has a three position thumb switch but is centre ON with two OFF positions, I does however have the necessary three detent positions.
All I had to do was to replace the fixed contact bar from the SL90 switch (two contacts) with one removed from a CB72/77 left hand switch, normally the lighting Main - Dip Beam which has three contacts on it. The moving contact and the thumb button from the SL switch were retained and everything lined up fine and worked with no dramas.
Fortunately, neither the SL90 or the CL77 have a starter motor and both use external wiring, rather than having it routed through the handlebar so all that was required was to replace the wires on the contact strip with some longer ones of the correct colours. The switch casting had the legend OFF - ON - Off engraved on it and filled with red paint but it came off easily with a fine file and some polishing. The German model switch is marked L and R but mine have a plain casting so you have to remember which way to push the button! All in all a bit fiddly but nothing more and a very pleasing end result.
The CB switch involved quite a bit more work, although the SL90 switch and the German Indicator witch share the same basic casting there is no starter button, contacts, retaining clip etc. and the casting isn't actually drilled to accept them. A further complication is that the hole drilled in the SL90 casting to bring the wiring through passes through the mounting point for the starter contact retaining clip so this needs to be built up with weld and the redundant hole filled in.
To make the CB switch actually requires THREE donor switches, the SL90 bas unit, the C72/77 dip switch for the fixed contact bar and a CB72/77 right hand switch for the starter button, contact and retainer. After getting the welding done you need to drill and tap a small hole (2mm or 2.5mm in the built up area to fit the starter contact retaining clip, quite tricky as it needs to be in exactly the right place or the push button won't!!
I have a load of picture I took when I did the work which I can pass on if you get the guy to contact me directly, where did he see my bike or find out about my switches?
As an alternative I understand there is a 1960s Suzuki, possibly from an early Cobra which is styled much like the Honda switchgear and will fit straight on but I don't know any more than that.
Sadly the guy who told me about it died earlier this year but I may be able to find out more from Jeff, I think he may have bought one of the Suzuki switches off Alan before he died.
I'll check with Jeff and let you know.
A follow up about the Suzuki switch is below.
I spoke to Jeff this afternoon but he didn't get the Suzuki switch I mentioned so I can't help with the Part Number.
I'm pretty sure it came from a mid sixties Suzuki so might be hard to find one anyway but it was styled just like the Honda switchgear so would look good on a CB77 or similar. Alan actually told me it came from a Dutch Suzuki spares dealer but not CMS.
My first attempt used a Kawasaki switch Left Hand switch with all three functions on it, horn push button, slider switch for indicators and a fore and aft knob for the dipswitch.
It looks quite similar to period Honda switches but was actually black so I sprayed it with Aluminium paint, it didn't look too bad but what I have on now is much better!