... I guess conceptually this really belongs within the Avalon-Excalibur-store framework, as it will sit along side AbstractJispFilesystemStore rather than on top of it...
Makes sense but I don't think it prevents you from implementing a Store in the Cocoon source tree for now, like the (broken AFAIK) org.apache.cocoon.components.store.impl.FilesystemStore which simply extends AbstractFilesystemStore.
It can always be moved to Avalon later on if needed, but it might be easier to work on it "here" for now.
What I don't see is how you can configure a different Store than the DefaultPersistentStore, have you figured this out already? Cocoon uses DefaultPersistentStore by default but I didn't find where this is defined.
-Bertrand
