In orchards we often see mowers that are 12-14' wide. This works as the floors are kept flat. I run a 10' in my pistachio orchard and it works fine. When farmers buy a flail from us, they often have a very specific mowing task and want a mower to minimize passes over the orchard floor for both compaction reasons and cost of fuel/manpower. You don't want to take two 10' passes and be left with a 2' strip in the middle that is not mowed, requiring a third pass. We do occasionally see mowing widths up to about 20', and that is done with a trailing mower (behind the first large mower) that is hydraulically offset for width. I've never sold one of those monsters, so I am not exactly sure how all of it works as far as getting power from one mower to the other, driveshaft angles and such.