Triggerbuttons without velocity sensivety can be realized with MIDIO128, MB64, MB64E… No problem.
To get velocity information you need piezo triggers (used in the edrum project. A analog circuitry is needed like described there).
OR you use special buttons. They have two contacs. One is opened or closed (depends) when you start to press down the button. The other one is triggered when you have pressed down the button. You can get the velocity information by measuring the time between these two states. I don`t know if anybody has tried this with a Midibox.
I think to achieve a accurate time measurement the buttons have to be connected directly to the core (no shift registers) and you have to assign an interrupt to them. So I think MIOS is no option for such a project.
I’ve moved your post to the old one, because it’s not really useful when you spread your questions over the whole forum.
If you have some programming skills, you should be able to merge the C based MIDIbox LC application with the DIN Velocity project (this is not trivial, but it works)
Without programming skills, the easiest way is the use of two cores