I know there are thinkpad hoarders with like 10 or 20+ old thinkpads. Seems to be a nice hobby, but you will rarely find one who builds a thinkpad cluster.

In the case of Raspberry Pi it is pretty normal nowadays to connect a bunch of them into a cluster and have some fun. In fact, it has become so popular, that you u can find stackable cluster cases and other Pi cluster hardware on amazon.