Which Bafetti model is it? They have some models with the typical keyboard layout of buttons: 11 buttons on the outer and inner rows, and 12 buttons on the middle row. Those have the usual accidentals on the upper most button of each row.

But then there is at least one model with 12 buttons outside, 11 middle, 10 inside. I guess that's the one you are talking about? Keith Frank sometimes plays one of those, but you don't see them any where near as much as the 11-12-11 types.

I don't know what the note assignments are on that keyboard layout. It obviously has to different in some way on the upper button(s) of each row.

It is possible to order a triple row with a stradella bass - but I think it has to be a custom order. I suggest you contact Karlitos Way. He's a dealer for Baffetti, Beltrami and others. I am sure he can set you up with whatever you want.