In case you missed it:
http://ansa.it/web/notizie/rubriche/english/2012/04/20/High-speed-railway-makes-inaugural-run_6749320.html I don't know if this will make a big difference for "back door" traveling, or even if it will affect the train schedules. But, just in case, FYI. Happy, safe travels.
bump. This is important news.
Here's another link to the proposed routes for the new Italo train. Note that this train will not be stopping at either Rome Termini or Milan Centrale. The train will be stopping at Milan Porta Garibalidi and Rome Tiburtina. According to what I have been reading, the Italo line will not accept Eurail passes. Neither will the new Thello night train from Paris to Venice. Finally, there is the new TGV International train that has replaced the Artesia train. This is a day train that goes from Paris - Torino Porta Susa and Milano Porta Garibaldi. Seats for travelers with a French pass or Eurail-brand passholders that have a Eurail pass for France or a multicountry pass that includes France will be limited. Any pass that does not include France will not be accepted. Seat reservation fees for the French pass holder is 15E for second class. For the Eurail passholders, it's 55E for a second class seat. http://www.ntvspa.it/en/nuovo-trasporto-viaggiatori/254/3/high-speed-railways-italy-city-time-frequency-travel