multiclumn PDF-Functionality is already present in the latest M92 Firmware 1.8.20130717 as well.
choose the sutitable Zoomlevel for columns like 200%,300%, 400% then choose PaperMode to navigate correctly thru the columns (Top-Bottom,Top-Bottom with the page turn button) and you can combine it with the auto-crop-function in the page-settings.
by the way the Paper-Mode navigates correctly thru multi-colums, which means vertical navigation, the same style of navigation but horizontal provides the Comic-Mode therefore one can navigate correctly thru PDF-Comics.
Booxtor showed it with the regular multi-column mode in comparison to the multicolumn-Mode combined with Auto-Crop.
https://www.youtube.com/watch?v=CPnN0p3BCME