We installed a Zepher chimney vent hood (from Build.com) on the exterior wall. The electrical was run up with the plumbing so the installation was straightforward, but it was a tight squeeze for the vent. I notched out some drywall to mount some plywood to mount the blower.
I taped the joints and hooked up the wiring.
Onto the chimney...
The chimney trim, included w/ the vent kit, needed to be trimmed at an angle to meet flush with the vaulted ceiling. I taped the cut line, and cut it with an angle grinder with a circular cutting disc.
A flapper vent was installed on the exterior and Voila - vent installed.