" I hope that gives you an idea of what I'm after. I'm a songwriter, not
a
producer, and need to take my song (i.e. melody & backing chords) and
have
the device provide me with a virtual cutting-edge Pop-R&B 'band', as if
I'd
walked in the studio and handed my lead sheet to a No. 1 Pop-R&B
Producer.

I think the short answer is no. Nothing like you have described here
exists.
And if it did, even though you might have original chord progressions and
melodies, no matter how "cutting edge" the arranger pre-set you use is, it
would
be instantly recognisable as that pre-set and wouldn't be touched by
anyone who
actually wants to be "cutting edge". That is, it might sound like
"cutting
edge" R&B the first time anyone gets it out the box but to any serious
producer/artist it will sound as cheesy as that bossa nova preset on your
grandmother's organ, purely because it is instantly recognisable as that
preset.

Sorry, but you need to put in the hard work to create original material if
you
want to succeed.
True but OTOH.....You can get a good basic idea of a tune you're flogging to
someone the way the original poster described....after all he's just trying
to sell his song ......once successful with that it can be properly
produced...
Len