firstly i apologise for not reading the whole thread but on the recent safety course i sat next to frank robinson (i was gobsmacked when he turned up for lunch, but on the course thats what he does) and he said one major regret was not completing a diesel r44. but in his own words he just could not get the darn weight down!!! mr robinson is crazy about low weight machines and simplicity.
Oddly enough I had a similar discussion with Frank Schweizer a few years ago right after they had sold Schweizer Helicopters to Sikorsky. Today Sikorsky is barely interested in even continuing the production of the 300C series, even less interested in sinking any money into diesel powered light helicopters.