Hi El1itehax0r.
Welcome to our Mattress Forum! 
On top of my head, one of our Members that make 15" covers/encasements is: Arizona Premium’s ,15" Bamboo - Wool Zippered Mattress Cover
You may also want to also peruse the mattress covers in the component post here.
There are many options for zippered encasements of a mattress. You can check out some of the more knowledgeable outlets like Allergy Buyers Club (or their sister site Sleep Buyers Club) are often great resources because they personally test all of their products and have good comparative descriptions of the different materials on their site.
Phoenix