That would really be a dream come true. Went from Frankfurt to Rome by train last year and it actually worked like charm but it would have been nice to book it all in one portal instead of booking at DB for the first part till Basel and then booking the rest of trip, Basel - Milano - Rome, on Trenitalia. Would have provided me with some peace of mind to know that even if the first train is late in Basel I will be able to just take the next train and won't have to argue with some Swiss railroad guys about whether or not I'm on a single journey and missed a connecting train or if I booked to separate journeys. The later would mean that if I had missed the connecting train in Basel I would have to buy new tickets were being on a single journey means that by some (already really good) EU regulation I would have been able to take the next train southwards.