James Bond - Second floor hallway

Or that same exterior stone as floor?

I have done faux marble in the past, and I have used real life sticky back floor tiles also,  where you cut them up and make patterns on your floor, but this will add height to the floor and I don't to deal with that going room to room. I will think of something but for now rugs are the answer LOL!

Parquet floor would look really nice here as well, you could even try a combination of 2 or 3 colors in a pattern to compliment the colors on the rails and ceilling. The style of your house reminds me a lot of High Gothic revival buildings, like the work of William Burges, these buildings would often use complex patterns of parquet or mosaic to decorate the floors. Before the 1900s carpet floors were not so widely used because it was harder to keep them clean (no vacum cleaners xD), so highly decorative flooring was trendy as it required less covering for the room to look fancy