Thanks for the post and insights. I should point out that we are not assuming that the format will be adopted by microformats.org. That will be Tantek’s and the rest of the community’s call. Not being within physical proximity of the people working on microformats in the Valley is challenging. So , we thought we would narrowly focus our collaboration and exploration on content reuse on a site a bit less intimidating to the average content creator. Hence, playtheweb.org. However, we are hopeful that the results will be useful to and possibly integrated into the microformats initiative.
Rob Linton is proposing adopting your stacking solution, but always maintaining the original node (source?) attribution.