Last rumour I heard was that the next lot of stuff that we're getting off Mainline are the domestic shuttles.......
In yer dreams!
Returning to the original topic, the MAN-JFK hasn't changed significantly since the advent of BACX. For the last few years its been a mainline 767, crewed by mainline pilots and BAR cabin crew from Manchester, with Ops control done by BAR in BHX and MAN.
AFAIK the only thing that have changed is they now use BAR cabin crew from BHX as well and BAR Ops has merged with BACX Ops.