Forrest McDaniel performs an experiment:
You may have run into issues with GUIDs as clustering keys, but another major problem is in columnstore. Smart people at Microsoft wrote columnstore in a way to take advantage of modern CPU features, but those CPU features don’t play well with datatypes larger than 8 bytes. Which includes GUIDs.
Read on for the demonstration of this, a clever workaround, and the ramifications of splitting GUIDs into two BIGINTs. Full points for cleverness, though like Forrest, I wouldn’t want to use this in production.