I remember reading an article ages ago in a Ford tuning magazine about an alternative to a turbo timer. If I remember correctly, it was essentially a small bottle, some tubing and a couple of valves. The idea behind it was that as the engine was running, the valves (attatched to an oil feed somewhere) would slowly syphon off a small amount of oil and store it in the bottle. When the engine was turned off, the oil stored in the bottle drained back through the turbos cooling ducts and achieved the same effect as a turbo timer. But this was a good few years ago and if I remember correctly, it was just a prototype modification on an escort cossie being tested by a tuning firm. Maybe someone like Graham Goode Racing would have an idea?
As this has no electrical connections and is essentially a stand alone system it would be ideal as an alternative to a turbo timer.
Cheers, Mark