The other day I witnessed the following scenario... A new node was added to a failover cluster, and a SQL Server instance was added to the node using normal methods. After adding the SQL Server instance to the new server node, an attempt was made to install SQL Server 2005 SP2. The install failed with the error message "No passive nodes were successfully patched" and "No passive nodes were successfully patched."
Turns out that KB 934749 details two methods for working around this issue. One method involves a hotfix. The second method, which I thought was interesting, involves failing over the SQL Server instance to the new node and then removing nodes that are possible owners. Once the setup thought that it was running on a single node, the install worked, updating the SQL Server instance and files on the new node to the appropriate version that matched the other nodes.