I've read thru the thread posted by thecontroller and it is interesting.
I can understand the reg bodies pushing for better safety (that's good) but don't know whether twins = better safety period?
I seem to remember the UK going through a period of fatal TwinStar crashes flying VIP/Corporates - the extra engines didn't help then!
I think the answer in the long run may simply be to produce really reliable, well powered and highly fuel efficient turbines so that twin safety, performance and economy is beyond question.