I had some made last year at the IMS show.
They really work well, but it takes some getting used to. They are much harder than the normal foam earplugs that I usually wear so a lot rougher on the inner ears.
That said, they work great!!! I use them with my iPod and on trips with the Autocom system. They were expensive...$175 I believe, but worth the money.
btw, I actually use them with the iPod to cut my grass too. They totally block all sound and work great.