The design does blow. My Etymotics almost fit. I got stereo sound but did not quite "lock in" two minutes wit a sharp exacto knife and they fit perfect, just had to take of about 1 mm.
I saw a whole pile of adapters at the Apple store. I don't know how much they were though. I'd like to be able to use my Shure earbugs but I like having the mic on the earbuds that came with the iPhone. Oh well.