ceiling
hide the ducting in 2 faux soffits or "beams" clad in drywall that run all the way along the center part of the ceiling. For this idea you can create other faux soffits to mimic the look of a clad beam. Can also paint the ducting itself glossy white and run it in two parts along the ceiling lengthwise (mid-level on the ceiling).
Shallow gabled ceiling. Love the paneling
do the faux soffit that's on the right, but on the left and install lighting on top (like here) to give the soffit a faux purpose. OR, just install white high gloss painted ducting along the outer edge of the room on both sides of the house! Doesn't need to be a fake soffit, can just be painted and cool looking, then we have the exposed brick on the other wall, and maybe same on fireplace side to give it an exposed feeling? or white painted brick
Pebbles
Q