Giovanni,
I had an Iorio-H model, which I'm pretty sure is the Elka 83. It had lots of white buttons with blinking red lights and could layer 4 instruments on the right hand.

I loved everything about that model, except that the organ sounds tended to be too smooth. I was using a large Leslie 760 and if I needed the full hard Santana style organ, it came out sounding like the organ at the old roller-skating rink on Sunday/family day. The organ sounds worked well for everything else, especially dinner music standards, light latin and things like that.

I used that 760 with a Cordovox CG7 and the rock organ sounds had a nice bite.

I heard the Concerto DA200 at the accordion club. It sounded great. I'd be happy to own that.

Don:
I notice that a lot of the midi-accordion players are still using the Ketron XD-3, even though they have looked at others, like the Midi-J. Members here who have the Midi-J (non-accordion players) seem very happy with the midi-J. Do you want to start using a keyboard, like the Tyros2, or have you considered other sound modules?

What kind of amplification are you guys using for the acoustic and the electronic sides of the accordion?