You'll be interested in following some news coming out about the next version of SharePoint this week at PDC. ;)

Perhaps not exactly what you're after, but there is a 3rd party product that can produce custom work flow and document flow in Sharepoint. http://www.sharevis.com

Before any document libraries can raise events on the server, WSS must be configured to enable events. The default configuration of a WSS virtual server does not allow events to be raised for document libraries, so you have to explicitly enable this feature before your custom event sink objects will be notified of events. You can do that through the administration Web site, by using the SharePoint command-line administration tool STSADM.EXE, or by using the WSS server-side object model. Enabling event handlers programmatically is simple using code like that shown here:

SPGlobalAdmin globalAdmin = new SPGlobalAdmin();

System.Uri uri = new System.Uri("http://localhost:8080");
SPVirtualServer vServer = globalAdmin.OpenVirtualServer(uri);

SPVirtualServerConfig vConfig = vServer.Config;
vConfig.EventHandlersEnabled = true;
vConfig.Properties.Update();

globalAdmin.Close();