You may also be interested in one of these. I found it while reseaching for the said arranger before.
2 2012-04-05 16:22:21
Re: KORG BACKING SYNTH (4 replies, posted in Recording)
Is this what you are looking for?
http://www.korg.com/microarranger
I also remember something that Roland put out quite a few years back that only has the arranger section with a small 2 octave keyboard. Kinda like a full size keyboard without most of the keys. Cannot remember exactly what it was called though.