As others have noted, without the Campari it's technically not a negroni - and you can try Aperol (makes it a Contessa), or being more faithful you could try another bitters.
Here in AU some bars make a fully Australian negroni, using local equivalents.
(Otherwise Most bars will use Cinzano as the default vermouth -- it's acceptable, but nothing special.)
Domestic versions of vermouth exist, eg. Margan in Broke, NSW make some delicious dry and sweet vermouths. Not common, though.
Same for bitters - there's the confusingly named 'The Italian', from the Adelaide Hills (South Australia) distillery, which is a magnificent take on bitters.
I'd suggest looking around for some imaginative variations local to your area, as there's a lot going on with these types of drinks lately (as per TFA). Great news for the sophisticated addict.
Or maybe go for some variations -- in addition to a Contessa (too sweet for me) you can look at the Hanky Panky, which is a delicious cocktail, and worth ordering just for the name.