After many months of deliberation here is the white paper that I have been working on to define 10G BPEL dehydration store purge strategies. You can find it here on OTN. The main goal of the paper is to provide SOA administrators a way to identify their SOA Data footprint and choose the right purging strategy that best meets their requirements.
Please give it a read and I would welcome any feedback for further editions. I am currently working on an 11g purging white paper due for release in early 2011.
Thanks,
Deepak