Found this old plug-in, Xpost, that comes very close to delivering a functionality that some of us who post at multiple WordPress blogs might find convenient. It even seems to promise near-realtime comments and post edits synchronization, and, before the developer abandoned it, he added a tool for sending useful metadata along with the post and comments themselves.
So far, it has worked for sending posts from this blog to my OT “Developing” blog, though I have had some odd difficulties getting it to work on the OT side: During an earlier experiment, I was able to crosspost from OT to CK MacLeod’s, despite the occurrence of what appeared to be a major error. Today, when I attempt to add this blog to the Developing XPost settings, I get database insertion errors, which I believe have to do with the plug-in setting up a general use database rather than sub-site specific databases.
So, test #1 (which was actually a multi-part/multi-post test) was from CK Mac’s to Developing. Interestingly, comments were updated from the target post back to the origin post, but not the other way around. Edits did not sync: I edited the text at the target blog and it had not effect on the origin blog. Will want to test both ways on this post, if all goes well or well enough.
Depending on the results, I may next have to do what I have thusfar refrained from doing: crack open the files and look at or even adapt the code. All tests thusfar have been “external.”
Text added to test synchronization, with crossposting for this post set to “on” on Edit panel. Expect: Errors but successful completion of edit. Mainly curious to see if post edits appear at CK Mac’s.
[minor edit performed at OT-OTC above, and now this – no edits to CK Mac post yet]
[first edit to CK Mac post – note: “cross-posting” to OT is unchecked]
[checking Crosspost from target blog’s post results in new Crosspost (new post) at origin blog. Am doing it again, this time with comments checked – instead of “syncing,” I expect a new OTC post to be created with same title, and possibly with the CK Mac comments]
[yes on second post created (using CK Mac timestamp so appearing earlier in timeline), no on CK Mac comments cross-posting, too. Before I delete the second version, which includes these edits so far, will want to see if takes up these new edits, and if comments at the target blog are cross-posted back to CKM’s]
). Go to our 
Post edits, but NOT comments, from origin blog (OT-OTC) appear at target blog. This functionality might even be desirable. Next will be curious to see if a) this comment gets xposted back to the origin blog’s comment thread, and then, b) whether edits to this post at CK Mac’s get xposted back.
Also still to test code-external
1) functionality between two simple single-site blogs
2) functionality with “crosspost comments” turned off
3) functionality if crosspost is turned on for a post after it has already been commented on