A hotfix is available to let you configure a cluster node that does not have quorum votes in Windows Server 2008 and in Windows Server 2008 R2 (2011-4-26)
http://support.microsoft.com/kb/2494036 Windows Server Failover Clustering (WSFC) uses a majority of votes to establish a quorum for determining cluster membership. Votes are assigned to nodes in the cluster or to a witness that is either a disk or a file share witness. You can use the Configure Cluster Quorum Wizard to configure the clusters quorum model. [...]

