Yes, it needs SCSI or FibreChannel. MSCS is definitely not the solution for what you are trying to accomplish. MSCS isn't something you would normally approach casually, and try to install on desktop machines. A standard hardware cluster setup will usually cost between $9000 and $150,000+, depending on the sorts of decisions you make about storage.
Have you looked into using Network Load Balancing instead of the Cluster service? That might not work either. It would probably still be cheaper for you to put together another desktop with identical printers attached to it and configured identically to your production print server. Leave it powered down until the existing print server fails...
ShackDaddy