Like you, I've done a lot of soul searching lately over this question. I'm Jewish on my mother's side, but we always thought that my father's Milano family was Italian. Then he went to Milan for a visit, where he was quickly told that he was Jewish not Italian.
So needless to say, we're all quite interested in finding the answer to this question. I have a Jewish friend who runs a Jewish genealogy site and he says there's no doubt that Milano is definitely of Jewish origin. There's too many of them that show up in the right places, especially Amsterdam.
The real question though is, are Milanos still Jewish? The answer to that question would have to be answered on a family by family basis, I believe. I'm sure some Milano families, through intermarriage, became Italian generations ago, whereas some Milano families are still Italian.
I would be interested if you find any more information, however.