You know, I realize it may be overkill for your needs, but I tend to agree with Notes on this. The Ketron SD-2 was way ahead of it's time when it came out, and the sounds are still pretty awesome, even today.
Having said that, on both Reverb.com and ebay, I can't find one. But, I can find a Ketron MidJayPlus player, used, for sale. It's in France, but I don't think there would be any issue getting it sent over.
https://reverb.com/item/67405536-ketron-midjay-plusYou can read the product specs here, as well as downloading a manual.
https://www.ketron.it/prodotto/midjay-plus-2You can see what a guitar player says about this.
https://www.youtube.com/watch?v=DsLXOM4fxkII will say he's playing the Pro version, not the Plus version and there may be things in the Pro that aren't available in the Plus version.