Hi Nick
Most TOTL/MOTL Arrangers can do this (Yamaha is I believe is one of the exceptions, although someone that plays Yamaha will be better informed on this) as they have dedicated Midi voice banks.
I believe the Korg PA800 is roughly at the PSR 910 price point, so this may be worthwhile having a look at.

Hope this helps

Bill
_________________________
English Riviera:
Live entertainment, Real Ale, Great Scenery, Great Beaches, why would anyone want to live anywhere else (I�m definitely staying put).