page, linked to by Lupin in the Ich stickied thread-
" In Oklahoma, university researchers studied a closely-related ciliate, identified as a "strain of Ich," in which the reproducing stage doesn't drop away but remains under the fishes' epidermis and releases the tomites from that secure position. This is a one-shot deal for the trophont, which dies in the process. The free-swimming tomites/theronts are still the only stage vulnerable to medication. In this close relation of Ich, the lesions are larger, looking like carp pox, flattened and waxy appearing"
Sounds like monster Ich to me.
But I think Twistersmom's explanation is much more likely.
In a minor Ich outbreak in one of my tanks recently, at 82 degrees the individual visible spots seldom lasted more then 24 hrs. If they are Ich spots, 7 days would be very unusual at tropical temps.
With fish being imported from all over the world and mutations happening constantly, its not inconcievable that the op encountered a strain of ich not commonly known in the hobby. That being said, I still think its unlikely.