Have you considered just using stainless steel sheet. I have done this in three properties. It looks good and is relatively cheap. I have details of a supplier that I have used in each case if you need it.

Try a slim porcelain sheet in a concrete look finish. The large format size means you'll probably need only one, so there'll be no grout lines. Have a look here, at the Portland 3.0. I think the Kerlite range also does a concrete look and is larger, at 3m long. The other advantage of a porcelain tile over actual concrete, is that you just wipe it down. Concrete is porous and will stain.

We have tiles that do not have a gloss finish. They are Encaustic, or at least I think that is what the style is called.

The tiles from Johnson in the UK are stunning. It appears they only come in large 30x30 ? I was thinking of doing some sort of tile art just in the middle of the backsplash with the rest just plain offwhite tile. However, with this large 30x30 art work, the background tile would have to be cut to size to fit the area I have and might look too choppy???