Alternatively one could balloon frame the wall at the gable ends and attach a ledger for the ceiling:
View model here:
https://3dwarehouse.sketchup.com/model.html?id=ub1aa30d4-a7c3-4320-8bc4-03fd128b5913
In my opinion a partially sloping wall gets complicated to frame. From an engineering standpoint the balloon framed wall is also the strongest option.