Looks like what is different here is the remote and mic. When I talked to a Shure representative, it didn't seem that they were this close to releasing a ltd version with the tweaked sound. He was going to forward my request and said if enough people were interested they may release it in the US.
Edit: While the above is true, i see that there is the option: SE535 LTD. Doh. Bad reading on my part!
So I just noticed something interesting on the US site. There's a model also listed as the SE535LTD but its in silver. I'm crossing my fingers for it to be the same as the red one; I've always loved silver more than red. http://www.shure.com/americas/products/earphones-headphones/se-models/se535-sound-isolating-earphones-with-remote-plus-mic