You know, I love a good story, however I think you are correct, it appears to be a shoe and pant leg, as a former search & recovery diver for the FD I have an idea what to look for as far as diving gear goes.
If you know about equipment maybe you can give some input on the questions at http://www.freerepublic.com/focus/chat/3125646/posts?page=391#391 . What do those things look like to you?
Yeah, I’m no diver but even I know you would see more than just shiny black and a bit of yellow, there would be nozzles and hoses and whatnot. Even the yellow thing is way too small to be a scuba tank.