Properly handbuilt wheels using quality components are generally your best bet for durability. 32 or 36 spokes tends to be the best for touring and heavier loads. Disc brakes won't wear on the rims and you won't need a machined brake track so it will lead to a stronger overall wheel. However plenty of people have toured on rim brakes so run 'em if you got 'em.

Hubs: Phil Wood, White Industries, Chris King and Paul Components make some excellent hubs right here in 'Merica. I am a big fan of White Industries (my road wheels are WI hubs and a new Raleigh build I am working up will also be WI) and my touring wheels are Paul Hubs (though sadly they don't make their cassette disc hubs anymore). Shimano also makes a decent quality loose ball hub in their XT and Ultegra hubs which are well liked by touring cyclists. If you want IGH then Rohloff is the jam, not cheap in any sense of the word, just super high quality and durable as all get up. Schmidt Original Nabendynamo or SON makes an excellent dynamo hub in various configurations that will match up to the finish of your Rolhoff and on the plus side will give you power to power lights or your USB devices. I had said they weren't my thing when I first built up my Co-Motion and after plunging into dynamos on my FG/SS randocross fun time machine I am sold beyond sold and am getting a second and third set for one for my tourer and the other for my hybrid and selling a bunch to customers as well and already thinking of next bikes and planning dynamo compatibility from the get go.

Rims: Velocity Dyad, Atlas or NoBS are popular options for touring bikes and are made in 'Merica. My rims are WTB Frequency i19 CX rims which are tubeless ready so they are generally a stronger rim because of that. However I personally wish I had gone with the wider variants. Astral Rims likely has a great product since they are made by the same company behind Rolf Prima and also made in 'Merica. I have yet to try their stuff but I am interested in trying their Leviathan rims. Sun Ringlé makes popular touring rims at low prices as well. I know some co-workers who swear by Mavic Open Pros as well.

Spokes: I use Sapim spokes for the most part and several co-workers prefer them as well as well as another well known wheel builder I know. However DT Swiss, Wheelsmith and Phil Wood (who make one of the most used and well loved spoke cutting machines out there) make fine spokes as well. Good butted spokes are really what you want and something like the Sapim Strong or DT Swiss Alpine IIIs are good options.

Nipples: I go brass always and typically go with Sapim Secure Lock Polyax but any good locking nipple will do the trick. However a regular brass nipple is not bad either just make sure you don't use some odd nipple with a proprietary wrench.

There are plenty of great wheel builders are out there and some people who do nothing but and some who are known for their wheelbuilding prowess but also do other things. Our shops have a few great wheelbuilders in the midst and maybe your shop might have someone as well if not, Bill Mould, Peter White and Sugar Wheelworks are excellent places to start and they can help with parts selection as well. Quality Bicycle Products AKA QBP has a wheelhouse and they generally turn out some decent custom stuff with any parts from their catalog so talk with your local shop and they can order you some if nothing else. They may not have the prestige of Bill Mould or Peter White but they certainly crank out quite a few wheels that are true and properly tensioned.