That's a really good question. There currently is no way to "donate" a hub to another account. I've often worked in-person with new hubbers, showing them the ropes of HubPages, how to write with keywords in mind, how to publish articles on HubPages, etc. I often show them from my account and we work together on a hub in my account and then we delete the hub and move it their account.
It would be so much easier after we work together on a hub, that I can push it to their account before publishing. I have a number of unpublished hubs-in-progress in my account that are actually my sister's because she and I worked together on them.
I also had a friend who didn't care much for writing online and he later decided he no longer wanted a HubPages account. Since he and I had worked on his two hubs, he offered the hubs to me. He deleted the hubs and then emailed them to me. I made changes to the hubs to better fit my writing style and republished them under my account.
It would be so easy if we could donate hubs to each other. That said, the bulk of hubbers probably wouldn't use this feature. Unless, of course, they maintain multiple niche accounts in which they want to keep "like" hubs together.
You might want to propose this in the forums. I know of a similar site that has this option.