AFAIK, no-one at the Korg forum is working on an entire soundset. Yes, there are talented sound designers, but they seem to be mainly working on individual sounds.
And, I'm also sorry, but simply sampling the sound of an existing arranger does NOT get you that close to the original. At least, not unless you turn off all the effects, envelope programming and LFO's, sample just the basic waveforms, and recreate the whole programming. Otherwise you get unacceptable 'munchkinization' of all the periodic variations (vibrato rates, envelope times, effects) and lose the velocity cross-splits unless you are anal about the recording process.
Not to mention, of course, you STILL lose the SA and Mega abilities without an OS that can do these tricks. Which, from what I've read, the MS cannot do.
I hate to be the voice of reality on this pie in the sky thread, wouldn't it be nice if there WAS an easy way to do this?
But it is still a herculean task to do even half baked, and of course, there is STILL the copyright issue. Wholesale theft of a product's entire soundset, especially if made commercially available, will undoubtedly have Yamaha's lawyers down on you like a ton of bricks.
This whole thing was done to death two years ago (if I remember rightly) and we haven't seen the product since.
And all this, STILL to only play non-Mega old PSR styles...
But I think the desire for it simply illustrates how poor the native library of MS styles is. If there were sufficient TOTL styles already in the box when you get the MS, no-one would honestly give a damn about some old PSR styles...