The requirements you descriped are part of my thesis in the study.
With my (study) friend I'm developing the following system:
It's a client, based on .Net to define processes or get processes from Microsoft Visio 2003 (ARIS EPC-schema) and create the processdefinition / image for jBPM (PAR). You can add/update/rename/integrate varibales, classes, swimlanes, taks, ... almost all jPDL 3.0 elements. There is a validation to check, if your processdefinition is valid (not just SAX-Level, its more logical level).
It's a service to transform ARIS EPC into jPDL 3.0. It works with the AIBP Client. Based on .Net & IIS. Send a Visio VDX (XML) file (EPC-Schema) to this service and get the processdefinition.xml back (not finished, need's the client to some stuff, that is missing in the EPC Schema and necessary for the jPDL).
It's a webapplication based on J2EE, JSF, Struts-Tiles... for the presentation layer of jBPM Workflow Engine and our own identity module.
It's possible to exceute/deploy/undeploy processarchives, add/update/remove users, groups and roles, has integrated JAAS security...
I will soon publish the webapplication with on our webserver. There will be a guest account to login and test it.
If you are interested in the stuff we are developing in our thesis, please send a mail.
The german page of the thesis is avaiable on http://aibp.dyndns.org
This should be not a new topic, should be a post reply for
Webbased GUI for creating/modifying workflow