I'm not going to vote because I don't have broad enough experience, but I wonder about these issues...
Can't you just remove the legs from almost any unit and build it in?
Almost everything wears out or needs to be replaced for some reason. The counter space will probably last longer than the pellet pit. There doesn't seem to be a consistent footprint size from manufacturer to manufacturer. So won't your friend possibly be faced with the problem of not finding a replacement unit that fits the allocated space?