I think I know what he's saying Zax..
Say if you do a sketch and have it set to 400x300 (one of the options) and then draw whatever on any part of the screen. When you go to trace it, it always traces the 400x300 area, not just the part that will be burned.
Not sure how you'd implement this, but maybe if there was an option to do a low power burn @ laser power 1? I suspect this is already possible by overriding the laser power, but if there were enough people that wanted it, could be separated into a button to help get a visual of what a full sized sketch might look like? I dunno.