It would be nice to be able to set background colors in the scheduler/calendar like you do with events. You set a collection of start stop objects that can start and stop separately from the time header. If I have a cellduration of two hours my one hour lunch will look like two hours.
If you want to display background objects that do not match the cell dimension it might be better to use a special kind of events for that.
You can apply custom CSS in BeforeEventRender to make them look differently (and match the background).