The Euston to Birmingham trains are often 350/2s, and the 350/2s even make it to Liverpool. They do crop up on the Crewes every now and again, although that tends to be when the evening 12-cars are the wrong way round, dropping the /1 at Northampton instead of the /2. Some of this will change when the 110mph timetable kicks in, as the /2s haven't been altered.
I don't mind the /2s for my journey into Euston, but my journey is a 30 minute commute. The idea of being on one for over two hours makes me shudder.