We have had to use an air admittance valve in our bathroom (for the vanity sink). The pipe is in the wall and goes about 2/3 up the wall. It is between the the shower and vanity.

We need to have a grill on the wall to have access to it and I think to allow air intake. There are metal grills available and we can paint it the wall color, but I was wondering if anyone had any creative ideas that might be more attractive.