Common transmission?
I wondered the same thing, and as far as redundancy with OEI, would it not be easier to mount both engines in the center fuselage and use a combining gear box just like a standard twin engine helicopter rather then have to run drive shafts back and forth through each wing. If I understand correctly the V22 can power both prop rotors off of one engine, seems like a lot of extra work to run the drive shafts that way.. to me anyway..
Inquiring minds want to know!