The "San Francisco" paint scheme on the Williams Peter Witt is actually Milan, Italy:
https://www.streetcar.org/stre...an-yellow-and-white/
If you're so inclined, you could ask http://www.customtraxx.com/ if they have anything in stock.
At one point, Walthers offered generic O scale trolley decals with things like "Please Have Fare Ready" and the like, but I haven't seen them in decades... :/
Hope this helps.
Mitch