Diki,

I entirely agree with what you are saying. At least Ketron made an effort with the SD2 and SD1000 sound modules to try and keep up with their flagship arranger sounds ( though only succeeding half way imho) but the others have left us in the lurch allright. Image Yamaha releasing a simple soundmodule containing most of the sounds to be found on either a Tyros5 , the Genos or even the cheaper SX900....I am sure many Korg, Ketron and Roland keyboard owners would go for it , if the price is right of course....I know that I would.
Still the existing KMA arranger is a great alternative , also because it can often be bought secondhand, and the cheaper yamaha PSR series like this PSR373 ( note the 7 !!!) offer a reasonable alternative.
You mention the Roland Integra,but let's not forget that is in an entirely different price range !!

regards
John