blengon:
I will connect the keyboard not to a real PC, but to different hardware, which have USB keyboard support but have typically no possibility to change the layout and if possibility is there (which is rare), than it have definitly no support for Dvorak/Colemak and similar
I guess I don't understand what you really want to achieve, then. Are you also going to relabel the keys when you switch the keyboard between different layouts? If you only translate the scancodes and leave the original key labels in place, I would have thought that would be extremely confusing.