No, there isn't, unfortunately.
I sometimes use the Catholic directory of parishes, because people might list that as place of origin instead of the comune, but even there, there is no Casanova or Casanova in Calabria.
http://www.thecatholicdirectory.com/directory.cfm?fuseaction=show_country&country=it
I highly doubt a Calabrian would say they were Neapolitan or vice versa, however. They were virtual "foreigners" to each other until they met here.
There is a Casabona in Calabria, however, and the people at Ellis Island are notorious for bungling the records. I know of a Chini who became Kinney. They spent the rest of the their lives down three generations explaining they weren't Irish.
http://www.thecatholicdirectory.com...ch_directory&country=IT&absolutecity=Casabona
It's in the provincia of Cortone.
According to this site, there's a lot of "Celanos" in Calabria.
http://www.gens.info/italia/it/turi...t=cognomi&cognome=Celano&x=0&y=0#.XOA9Q8hKhPY
There's only one Celana, and it is in Campania, but when there's only one variant like that I find it's almost always that this family is mis-spelling it.
If it were me I would write to both parishes in Casabona Calabria to inquire.
https://www.familysearch.org/wiki/en/Italy_Catholic_Church_Records_(FamilySearch_Historical_Records)
http://geocities.ws/paulanigro/italian-genealogy-online/italian-form-letters.html
You could also try to hunt out the parish church in the Cazanova neighborhood in Napoli, just in case.