We have been to Italy, and as it will be a Catholic ceremony, we're aware of the paperwork issues and the back-and-forth/hoop-jumping required on our end here with the local parish and over there with the Nihil Obstat, etc. The ceremony would be (not surprisingly) at Santa Susanna as they often administer for couples interested in getting married in Rome from abroad, and we've thought about Oct/Nov 2010 as a date (though we are flexible). We visited Santa Susanna and looked into the requirements, and we're getting the ball (slowly) rolling over here with our own parish. Naturally, we'd have to sit down with the pastor over there again to firm up any plans once we have them.
We won't have more than 10 people in the "reception," I don't think, which is why we're kind of a special case, I suppose. We can't rent out a hall or a villa, though, due to cost, and so we're feeling out just what is involved in small locales that might offer a quality, unpretentious meal in a cozy, private setting for our party.
The idea of "BYOB" was simply to cut costs; literally, we were thinking of a few bottles of Prosecco that we'd bring for toasts ourselves, even though house wines and the like are thoroughly inexpensive across Italy. As the notion of bringing in wine is something of an understandable affront to restaurants, the notion of bubbly might be less so, however (we aren't big drinkers), considering the occasion.
I'd hardly describe what we're shooting for as an afterparty, though; just a meal, some toasts and general familial get-togethering.
We know we could consult with a wedding planner in Rome, but we thought that general inquiries might turn up some places to go or look at without forking over an initial consultation fee.