Yes, definitely a nice feature request, even more so exciting if you are willing to help work on it and contribute to the communit :)
Please raise a jBPM Jira for this and describe your requirements.
Rather than having a set of process vars, like Maciej was saying it would be nice to have "process templates" which are user configurable and allow users when create a new business process to say "use template X" and that template would be imported into ther model. The templates themselves are valid BPMN2 models that can include not only process vars but also a set of nodes that users can start from..WDYT?