Looks like in this one they used wood paneling to actually build the whole hood and an extension up at the top.
Q
This obviously is more square that your hood but it has just painted drywall above the hood to get to the ceiling.
Im not sure if I have the measurement all the way to the ceiling to know if this is an option to stretch out the hood to go to the ceiling.
This one has drywall going up to the ceiling above the hood.
Looks like in this one they used wood paneling to actually build the whole hood and an extension up at the top.
Q