Hallway wall niches and windows

We are looking at putting in some low windows and some wall niches in the hallway of the house we are building. but we are looking for ideas in how to structure them. We are thinking low windows to let in light, but have the niches more at eye level so we can feature some photos, decorations etc in them.

The builder has said that any windows and niches wider than 500mm will go across a stud and will therefore need some extra support above and below - which I presume means extra cost. So we are trying to decide whether we go for long windows and tall vertical niches, whether we have niches directly above the windows or offset in the gaps, and how big to make the niches.

The hallway is quite long (just under 7.5m from the front door to the end) so we are thinking at least 4 niches along it. But do we go square or rectangular? Do we have square windows or long rectangular ones (like 1200x400mm). Do we put the niches directly above windows or in the gaps?

If anyone has any photos or ideas of things they have done or seen, it would be appreciated!