Welcome aboard glennv! Yes ;-) You can actually have (almost) any number of layers you wish to have. You do not have to give up buttons for that matter. Your buttons will be connected to DIN modules. A single DIN4x module can handle 32 individual inputs - if you go with a button matrix, your 8x8 buttons will need 16 inputs leaving you with 16 open inputs. I don't know a lot about the Midibox64 source code, but a simple "send data when a button is pressed" app isn't much work when you start with the skeleton application, which already does most of what you need. I don't think you'll need to worry about banksticks unless you wish to have some buttons active in different layers at the same time. Personal opinion: What do you need the 8x8 LEDs for? I'd go with your 8x8 button matrix and add an "up" and a "down" button or a rotary encoder to switch through the different layers. And of course a 7-segment LED display (or some LEDs) to display the actually selected layer. (kinda like in the attachment). Cheerio, nILS