UPDATED with product link
Can't remember which building materials store it was but I've seen copper and stainless looking back splash tiles that come in panels maybe 3' x 4'. You trim them as needed and adhesive them onto the wall.
A guy on RV.net who had a 5er made to his specs by Space Craft Mfg. added these to his new 5er kitchen in a copper color. Look really nice. So long as they can take the heat, it's a great idea for a trailer due their light weight, ease of cleaning and ease of applications.
I am thinking about this for the next trailer.
Jim
UPDATE:
I was in Menards today and saw the backsplash material I alluded to above. The brand Menards carries is ACP. The material is referred to as thermoplastic.
Here's a link to the product. Not sure what the surface temperatures reach on the back surrounding the stove when it's in use, but the max recommended temperature of this material is 140 degrees F.
From the Mfr's FAQs:
Can I put up backsplash panels behind my stove?
Even though the backsplash panels are fire retardant, they can be deformed by excessive heat. The panels can be installed on the wall above the stove, but not behind the stove. Be sure to keep toaster ovens, cooking ranges, etc. 2-3 inches away from the panel's surface.