I beleive it's been around in the States for a year or so on their 'flagship' outboards - Optimax and high power 4s's. It integrates somewhat into their 'smartcraft' system which is a computer controlled instrumentation system which is available currently on the aforementioned engines in the UK, these things just take some time to reach europe.
The idea is brilliant and i must say having 1st hand experience of Mercurys waterproof connectors i think it'll be RIBproof aswell - i recently discovered one of my connectors has been sitting in 2 inches of water for a few weeks, and nothing has failed on the engine - taking it appart it was not even damp inside.
Although this system, i suppose, is a potential for Mercruiser inboards it's very much a Mercury development so i don't think you are going to see it available for you boat for some time Brian, anyway i thought you were getting a new one? I guess you'll be staying diesel though?