I hear that Enstrom are working on a stretched version of the 480B
Thats not one that I have heard. Been to the factory a couple of times in the last year or so and havent seen anything that would confirm this, but then that doesnt prove anything either way.
Other rumors include a 200lb gross weight increase for the 480B, which makes lots of sense and I am told may be mostly a matters of testing and certification, not lots of new development. Also a return to elastomeric dampers for the MR, which Enstrom tried a few years ago, but had some problems with and withdrew from the market. Both of these would be meaningful improvements, but no "official" word yet.