An open source CMS (eXo) has got Workflow (Bonita) integrated to it. http://docs.exoplatform.org/exo-documents/exo-ecm.services.workflow.impl.bonita/index.html  One thing very hard for any other vendor to chase Sharepoint is that they lack the e-forms feature found in infopath. I guess Infopath's only competitor is Adobe PDF ...