personally I think jawe is a ideal workflow process definition tool, bonita is a open source project which introduce a new worthwhile item-Jnlp, and the performance of OBE is not good enough. If you can integrate jawe and shark which provides a main-structure of workflow system according to wfmc, you can develop yourself product.
By the way, I'm study workflow and wish communicate with those who are immerced in it or have interests to it.