Well, went to the local shop today. A lever on the wall looked like it'd fit if it was milled to be a bit thinner. (Even had the brake light switch actuating paddle part...) Parts guy told me it was spec'd for an "old gold wing."
Reason I asked was I was thinking of using a modern offroad clutch lever on my bike with the "hot start" lever (such as an ASV f1 or f3) to actuate the decompressor. Figured I'd want to go with a matching brake lever on the other side if I went this route.
Left the store with an MSR lever which looks similar enough to the stock lever blade shape that I think it'll work, but am also thinking of sticking with the more vintage-style separate decomp lever blade/perch.