Is it possible to remove a database server from a cluster resource, but keep it running on the node I was wondering if anyone knew whether it was possible to delete the cluster resource, but keep all of the disks and sql instance running on the node instead? So if I was to delete the cluster resource, would the instance continue running on the node?
No. The instance is configured to use cluster resources and as such if the cluster is removed the instance will not function correctly. 

If you like to play with fire in an experimental-not-in-production-learn-by-trial-and-error way, you can do the opposite of How to move SQL Server from Standalone to Cluster environment.