I know this kind of fringe but something I keep comming back to as I move to more Flow based metrics and a way from velocity. I look at flow in weekly increment. So team X does 5 stories a week as a trend. As a team understands what a product owner wants in a feature and breaks down the work in to stories you may see that we can deliver that in a 1 week or may be 3 weeks. A lot of companies like a 2 week sprint so that has a team looking to fill a sprint with stuff for a week in the first range or in the second filling a full sprint and half the next. You end up with add stories in the fill the second week of second sprint.
Planning sprints becomes about value chunks instead of value + some stuff that fits.
I would still cap all value chunks at 4 weeks, ceremonies would be held still and would not recommend this to brand new teams.
Would love to hear some opinions