On the Atom front, I've just added a proposal to the Wiki: PaceSimpleResourcePosting. The abstract is:
This proposal extends the AtomAPI to allowfor a new creation URI, ResourcePostURI, to be used for simple,efficient uploading of resources referenced by a separate Atom entry.It also extends the Atom format to allow a "src" attribute of thecontent element to point to an external URI as an alternative toproviding the content inline.
This proposal is an alternative toPaceObjectModule, PaceDontSyndicate, and PaceResource. It is almost asubset of and is compatible with PaceNonEntryResources, but differs inthat it presents a very focused approach to the specific problem ofefficiently uploading the parts of a compound document to form a newAtom entry. This proposal does not conflict with WebDAV but does notrequire that a server support WeDAV.