I've got the latest Final Cut Pro X and would like to have my video-projects at a custom location. How can I pull this off? I couldn't find anything in the settings.
Sadly, you can't.
You can only move projects to another drive, but you cannot specify the location. If you have multiple drives, select the project (in the Project Library) you'd like to move and in the menu select File > Move Project.
I think you should also be able to drag it to your drive of choice.