He could tile the backsplash, and silicone the joint. That is typical of all other tops exept a post form fomica (curved)anyway.
Sounds interesting enogh, but I would build a cutting board one first and see how it handles the wear and tear.
They also make a poly resin for bar tops that is self leveling and goes on thick. It is available ,look around. It is for the bars where folks put memorabilia stuff on top and seal it in so you can see it, holds up pretty good too.