I've been led to believe the stages on east side of the A470 are now unavailable as you say but Maesgwm is theoretically still an option? I can't really see it being used though, as managing the spectator traffic/access wouldn't be easy. I imagine it'd be hard to justify the faff required for such a short stage.
Drws-y-Nant was apparently due to make a return on a National rally this year.