Custom Foam Board Slip Cover

I’m looking for an experienced sewer who can sew a custom cover for a foam board (48”x48”x1”) with a 50” zipper along the bottom and up the sides a few inches. The job should be pretty simple, but I want to make sure it is very fitted and not loose at all. I’m looking for just one cover to start, but could potentially be asking for up to 24 if the job is well done! (Pictures for reference)