Not sure if I am asking a question or telling a story.
Would you ride through Africa or around the world on new model hollow bottom bracket and hollow crank arms? I am sure they are strong but you won't find a replacement and it is hard to work on them.
I helped a "Germany - to - South Africa" tour rider fix his crank/pedal this week. He had a hollow bottom bracket and hollow crank arms. Before Nairobi, Kenya his right pedal came lose and he must of buggered the threads (english was a problem). After failing to find the drive side crank arm in Nairobi they rebored the hole and screwed an insert in and brazed it. In the end he had a permanently fixed pedal that was not 90 degrees to the arm. He rode on south and two days later met me 3 kms from my house pedaling happily through Arusha.
When I stopped him on side of road and offered any help he pointed to crank. I figured he needed to grease or something. In his almost non existent English we decided he stay with me and use my tools. I have a fair amount of tools and spares, and started offering the crank off my wife's mtn bike . Then i realizied he had splined hollow crank an all my stuff i 10-20 years old. Almost buggered his bottom bracket spindle with my slightly broken crank puller. When we took off the pedal the insert came out too.
I forgot to take a picture. It it took us two half days standing around machine shops to get it right. We rebored the crank arm pedal hole. Made an insert with thread on the inside and outside and a flange on the inside. If I didnt stay around they would decide on other alternatives that never worked.
Me I think I stay with solid crank spindles and solid crank arms. But then I find hard to find parts for 10+ year old bikes on line. We finally have modern bike shop, but he only had road cranks.