I just delivered a set of my wheels (mu hubs) with NOS Shimano 6 speed cogs on a current 11 speed body. I trimmed down the axle and spacers on the left side to the bikes stock 126mm spacing. The 126mm is as narrow as I can make my hubs, and my hubs cost a lot more. I love the availability of 120 cassette. This makes using 120 frames much more sustainable. Sourcing cogs and spacers is still easier than finding NOS freewheels, plus the cassette style hub has a much stronger right side axle with the use of an outboard bearing.