Epiphany:
You can quite easily have a wall end at a non-normal angle (ie not 90 degrees) by using another very thin termination wall set at the desired angle to the wall being terminated. For instance, a GWB and stud wall can be terminated at a 60-degree angle by using a GWB-only wall that caps the stud wall. An even thinner "dummy" wall could be use to simply terminate without any wrap effect.