Lyndon-
As far as I know these switches are not being made nor have they ever been reproduced, which seems odd. The switch itself is rather frail being made of a cardboard shell which means they tend to have a short lifespan under the best of conditions.
On two past occasions (in person), I suggested to Bob Drake that he should give some thought about reproducing these things. The basic switch fits '35-'37 which means it is not a unique model creation. And, as you know, this switch is a single-step off-on which shouldn't make it a complicated item to make. I also suggested to Bob that "if" he did repo the item a two-step alternate would be nice as it would also provide a switch for fog lights. Bob was polite but I could see he wasn't interested.
In the meantime, while you search you could use a '49-'50 headlight switch. It has more leads than what you need but it can be "somewhat" modified to look "somewhat" like the remaining knobs (choke, throttle and lighter) with the addition of a repo knob which are readily available from several sources. Other than that you are between a rock and a hard place trying to find the correct switch.
Good luck
Tom