you gave a lot of use full information. I send that guy for 260 euros engraver a mail. He sad I could cut veneer(google translator translated like that from furnir ), but something which is harder than veneer wouldn't be possible.The laser thing the stiffness wouldnt really matter, or the stepper motor power I guess, just the laser power. No clue on that part.
Id guess Marcos' post would be more useful there