Custom Earbuds | Molded Earphones | Decibullz
Obviously not "ear plugs" but if you're using IEMs these seem like you'd get some decent noise blockage in addition to a robust and comfortable earphone. You just insert a Skullcandy or other similar size earbud in after heating up in water, then mold it to your ear. And you can re-mold it if you goof it up.
Have you tried these? I have a set of skullcandy phones that I use all the time and these would be an awesome upgrade