If there was an option to lock/unlock the speed buttons. It would take away a great frustration in the game.
I don't know how many times i have moved a moved a single speed button off a bar. Or pressed [-] or [+] instead of [0] and changed the row of the speed buttons. Or Relocated a whole speed bar by mistake.
Usually these things also occur in the heat of battle or worst possible time.
Being a programmer id say this change would also be quiet simple as well.
Possibly just a checkbox in the options menu.