Our kitchen lacks any sort of outside venting. I am planning to install an over-the-range microwave / fan, inspired by our friend Michael who is planning a similar project. Such a fan is too tall, however, for the existing cabinet in that space. I removed it with a thought to rebuild it shorter, but now I think I might just install an open shelf in that space instead.
These cabinets are held together with glue and staples. Ah well, someday we will replace them.