Wow, I love it! I hope someone has some answers for you.

The continuous appearance is achieved, in part, by the use of enormous tiles. For example, a Kaolin Chambord Grey Limestone tile is 1200 mm x 1800 mm (approx 47" x 71"). You might take a look at the Atlas Concorde Marvel porcelain tiles which can appear to provide a continuous appearance based on the photos. The effect depends on the product and how they're arranged.

Kaolin has 30”x60” tile. Atlas’ smallest is 47”x110”. Slabs that big are more prone to damage and have to be cut and installed by specially certified fabricators. There are a dozen or so companies that make large slab porcelain like Atlas. I’m trying to find a smaller alternative, like Kaolin, that is more manageable.

"Atlas’ smallest is 47”x110”....I’m trying to find a smaller alternative, like Kaolin, that is more manageable."

No, the sizes available are a function of the style as shown in the Atlas Concorde Marvel technical specs starting on page 128. Most tiles are available 30cm x 60cm (12" x 24").