"if your frame had been built with an offset back end," what do you mean by offset back endFor tandems and expedition touring, 36 spoke wheels that have been properly designed and constructed are sufficient.
The small boost in durability you'll get with 4 extra spokes isn't enough to make buying "boutique" hubs worth the significant price increase.
Now, if your frame had been built with an offset back end, you could have used 32 spoke wheels and had much more evenly distributed left and right spoke tensions! In such cases, the Maxfoot wheels are reliable and amazing for long touring.
Soma Saga Disc brakes is 135mm Rear