I recently bought a 10-speed Sunrace freewheel.

Available only with 11-36t ratios, it's a bit of a heavy beast despite having a couple of alloy spiders. Well made though (strong enough for e-bike use).

I was going to remove the 11t and shorten the body so that the lockring would move inward to meet the now-smallest 13t cog.
The lockring threading does extend far into the body, which bode well for my plans.

My freewheel came with a missing thin supplementary spacer between the 2nd and 3rd-smallest cogs, so I returned it. I was also less than thrilled that the large cog didn't sit any further inward than on a standard freewheel with 28t. I was hoping for some relief here that would improve wheel and axle strength, since larger cogs allow the derailer cage to follow the spoke-bracing angle inward.

These freewheels are almost $100, so there's that. But the design is all-new, with the freewheel body actually secured with a larger-diameter locking cone on the non-driveside!

Campy cassette spacers appear asymmetric but the actual cog spacing looks quite symmetric across the range.
Campy 8s lever indexing works well with a modern 7s freewheel or cassette using an 8s-vintage Campag derailer.

The 10s Campag lever indexing will work with Shimano 8s cassette spacing using a Shimano derailer.

The 10s Campag lever indexing will work with Shimano 9s cassette spacing using a Shimano derailer with modified cable anchoring.