Apparently Ladino was used as a trade language throughout the Mediterranean/Adriatic, and Wikipedia lists it as being "native" to Italy [1]. There also are regional Judeo-Italian dialects, including two from Corfu [2].
My internal map of Italy isn't very good, but given the 'size' of the populations that must speak or have spoken these dialects, I'd guess there was a dialect specific to Sicily.
I think you misread the origin of the Judaeo-Spanish ladino. From the wikipedia page [1] :
"This Judaeo-Spanish ladino should not be confused with the ladino or Ladin language spoken in part of North-Eastern Italy, which is closely related with the rumantsch-ladin of Swiss Grisons (it is disputed whether or not they form a common Rhaeto-Romance language) and has nothing to do with either Jews or Spanish beyond being, like Spanish, a Romance language, a property they share with French, Italian, Portuguese and Romanian."
"This Judaeo-Spanish ladino should not be confused with the ladino or Ladin language spoken in part of North-Eastern Italy, which is closely related with the rumantsch-ladin of Swiss Grisons (it is disputed whether or not they form a common Rhaeto-Romance language) and has nothing to do with either Jews or Spanish beyond being, like Spanish, a Romance language, a property they share with French, Italian, Portuguese and Romanian."
[1] https://en.wikipedia.org/wiki/Judaeo-Spanish