Wow, you certainly have ressurected an old thread :) You should really check out the improvements jBPM Designer has gotten over the last year+ : http://surdilovic.wordpress.com/. We have just released Designer 2.3.0.Final as well: http://surdilovic.wordpress.com/2012/07/26/jbpm-designer-2-3-0-final-released/.
The tie to the Guvnor repository is still there, however will be lifted in the next Designer release. We are working on alternative storage options as we speek.
Hope this helps.