I don’t know the do-ability of that idea, but it would be great to be able to use a 2nd keyboard on renoise, as a step sequencer, or grid controller (or, in the future, Cells controller).
A few years ago, I took an old ps2 keyboard, found the “matrix” for it (a keyboard is a X and Y axis of combinations, the matrix is the “plan” of how keys are played, for dummy example “e” will be the combination of X:1 and Y:12), and then I built arcade controllers for my arcade cabinet with it, finding the best combinations to avoid gosthing. Once you figured out the matrix, you just have to avoid to have more than 3 controls in a row or a line, and you can dramatically minimize the key gosthing doing this. Of course, you cannot map 100 controls keys, to avoid gosthing you have to limit the amount of keys, but you can still have a LOT of controls (my arcade cabinet 's got 16 buttons and 2 joysticks, wich give me 28 ON/OFF controls without gosthing…That’s for Street Fighter, so for music with a limited ghosting, you should be able to go up to make a grid of 4x8 controls easily IMHO).
Once you dit that, it’s simple to wire arcade push buttons, and make something sturdy and eficient. Or you can just remove the useless keys and paint the other ones for easier work, etc, etc…For almost nothing, you can have a nice trigger/on-off controller.
That 's the easy part. The tricky par is that once you plug two keyboards on a modern OS computer, especially in USB, the 2 keyboards act the same and are considerated as the same keyboard (as far as I know). Conflicts between the software or OS shortcuts, especially. Perhaps blocking the “key controller” in Caps lock mode could do the trick ?
The other problem would be the need for a special mapping function in Renoise, for that kind of controlers. A way to isolate the “fake” keyboard and map it.
Sounds not easy at all. But I tought about that, so who knows ?