The title "rex romanorum" (King of the Romans) was used. This implies, that the elected king has now the right to travel to Rome to become emperor.
(In the early Middle Ages long before the Electoral Council it was "rex francorum" (king of the Franks); some popes used "rex teutonicorum" as an insult, references to Germania/Germany appeared in the title only after the Middle Ages (but they appeared), -> You need to be really really careful with terms like Germans or Germany (it is complicated) )
While it seems unlikely, that an Italian ruler would be among the original Electors (they developed when the empire was in chaos, and it's authority over northern Italy wasn't anymore).
Later, when it became possible to create new electors in the 17. and 18. century, it would be possible under the right circumstances to give this title to an monarch in Northern Italy.
I don't know the exact legal rules for creating new electors. (It would probably help the Emperor if he could get the support of the other electors and other principalities in the Imperial Diet).
It is probably good for the prestige of princes and dukes to gain the elector title. If you are already king, it wouldn't mean as much prestige.
Maybe the emperor (Habsburg) has or wants to give a protestant duke in northern Germany an electorate to gain political support. Now the other catholic electors are unhappy. As a compensation to maintain the catholic majority, he now gives an electorate to a catholic northern Italian ruler (Savoy or Tuscany??).
But if Savoy manages to gain with Sardinia a kingdom, it probably won't care that much about an electorate. Another problem I see with Savoy, is that it is pretty close to France. French pressure could influence the way Savoy would possible vote. This could create some skepticism to the idea of giving them an electorate.
I don't now much about Savoy and Milan and their internal policy. But Milan has a long tradition of being one of the main opponents to Imperial Authority over Italy. Would it be weird, or could it become a problem towards the citizens of the city, if a ruler accepts an electorate (and therefore strengthens the position and presence of the Empire in Italy)?
If the Emperor is Protestant (while Italy remains Catholic), any Imperial Authority over Italy becomes almost impossible. A protestant Emperor needs some really good reasons to give an electorate to a catholic Italian (it is probably not entirely impossible, but I can't think about a plausible way it could happen).
You need to be aware, that it is probably difficult to create new electorates. You need to maintain the careful balance and peace between Emperor, Electors and other principalities, as well as after the Reformation the peace and balance between Catholics and Protestants.