I am confused with the statement that they never fit. If the builder or cabinet maker can not build the cabinets to fit a liner I would be a little cautious. If the builder is is going to just build that part what will he be using for the blower/filter/lights? I would not want to keep the wood clean or wonder how long the finish will last. It looks like you will be having a pro style range that will put out a lot of heat, steam and grease so I would press him to have some kind of metal liner inside wood canopy.

Thanks regbob! That's what our gut was telling us, but we really don't know much about this stuff so your thoughts mean a lot! We'll go back to him and tell him that we'd like a metal liner.