As usual, I find that I was way ahead of my time. Quite some time ago I made a similar gadget, but out of soft plastic, so that it was fairly easy to collapse and fold up and carry in the field, even backpacking. I used it to change lenses without dust contamination. Problem was, that it took too long and you don't want to be messing with such a thing while the light is best and rapidly fleeting. Uh, anyone want to buy mine? Same deal as the ebay thing; no guarantees, you buy, you try, you're stuck.
