It's typical of other period fixed hubs as there's enough threads to catch a freewheel. I prefer fixed over single speeds though so I'm thinking a Sports frame will be be the way to go. Or a 48/49 Lenton Clubman. Hopefully the brake will work well enough to take the stress off my aging knees. I've had 3 scopes over the years and really don't want any more.

And a tandem is certainly a good possibility even though it's called a Solo.