Hi guys,
Addendum for this particular piece:
When you find "full band" files that you want to make into piano reductions, there will also be times when you may need to change the pitches of some staves to accomplish a good (and playable) two-hand piano piece
For example, in this particular file, there is a staff named "piano bass", but it's notated (and played) in the file in the treble clef. If you just leave that and do the reduction, then it crowds out the melody, and makes a sheet-music nightmare (as Djim so poignantly pointed out). Something as simple as (1) selecting that staff (2) using Region/convert to selected notes and (3) lowering the pitches by an octave will give you that same bass line, but in an actual left-hand part that complements rather than confuses the right-hand melody part.
Also, the violins, strings, and guitar parts are really accompaniment chords, so those staves can be lowered an octave to allow the left hand to play the accompaniment chords while the right hand plays the melody parts of some of the other staves.
So, shifting those staves' notes down an octave, and selecting "all staves" in the Piano reduction wizard gives the following result:
BABAR-BassShifted.not
It's still a bit daunting (check out those 6-note left-hand chords in measures 9-11

) but it's a much more promising start, and can easily be edited by removing those "extra-pinky" notes (eg. from the six-note chords), or other "clutter" notes that aren't essential to the piece to give a playable two-handed piano piece. The rest of the editing really will depend on your tastes and skills, so have fun with it!
Enjoy!
Sherry