I don't know about those trips but I spent a few mpotnhs in Italy, live in a neighbouring country and have an italian sister in law.
I personally think that there are many countries that are much more interesting during christmas. You certainly know that there is a huge difference between the north and the south therefore it's hard to predict the weather (there are huge mountains and snow in the north but you may have nice temperatures in Sicily) and the atmosphere. Surely the nothern part would be more atmospheric during christmas except for Rome where you can go to St.Peters for christmas mass.
Concerning lights and christmas markets: you definitely can't compare Italy to France, Austria or Germany you get more christmas feeling in those countries, especially Nuremberg, Paris, Vienna or Salzburg.
Italy is rather simple in christmas matters, until recently children haven't gotten big presents, sometimes only sweets and there aren't many towns with lights etc. probably because of the church.
The appealing part is that it's much less commercial, but somehow I think the atmosphere is lacking. I love Italy but I never go there during christmas time.
Of course the itinerary would be interesting...