Buying from Italy
I definitely agree with libero: buy from north Italy if you have to, the Veneto, Emilia Romagna, Piemonte, Lombardia, Tuscany, Friuly Venezia Giulia (the north districts) are generally safer.
Also make sure you buy at least 3rd party insurance as in Italy and in Europe in general we are very strict on this, insurance is not cheap either especially if you don't have a no-claim history.
In Italy the bureaucracy is a real pain and for what I remember (I left Italy a few years ago) sometimes it deters you from buying, I remember waiting more than a month for my bike reg certificate back in 1996 (and the transition tax was something around £200) I would expect things have changed now (especially the heavy tax) but I am not sure. I can get some more info for you if you need, still have family back there.
I know buying in Germany is quite straightforward, I personally like the UK system where you can buy a bike in 10 minutes:
-go and see the bike
-pay the seller
-seller gives you a section of the V5 (vehicle registration document)
-seller posts the other part of the V5 to the DVLA (Driver Vehicle ..something.. Agency) and then the DVLA will send you a new V5 with your name on it to your nominate address (it takes a week)
-in the meanwhile if the seller has internet connection at home you buy insurance online with your new bikes details (immediate cover) - Bennett is quite popular but there are many around
-ride off, the bike is yours
If you need help to translate from Italian I can help you no problem, also French is not a problem unless it's very complicated.
All the best.
... and Nelly The Elephant packed the trunk and said goodbye to the circus...