Just a thought but I have had several opinions that archiving on the net is probably the most reliable. Well run ISP's will have back-ups of back-ups and re-instate if there is a problem. But longevity and the net are not proven bedfellows and maybe the clues are negative. Still it is a thought.
With the inexorable slide in the price of silicon we might expect Flash (etc) to be cost effective soon, how important are the data?