I did some initial testing, and MultiBlog is working great. Unfortunately, I am not 100% comfortable release to the public the code that triggers the rebuild for other blogs. It works for me so far, but I am not certain that it will not cause problems at a later date. I put in a feature request with 6A, which was promptly taken care of, and with the next release of MT, I will be releasing MultiBlog.
For the time being, I will just be working on the setup interface (defining which blogs will trigger rebuilds of which other blogs, etc) and trying to come up with more features. Anybody have any requests? The only thing I have come up with is the ability to move entries (including comments and trackbacks) between blogs.
One thing I'm struggling with at the moment is the fact that MTGlobalEntries doesn't support the category attribute.
Basically I want to list all entries in 3 blogs displaying in chronological order but only if the entries fall under 5 specific categories.
MTFilterCategories is no help because it doesn't act like the MTEntries tag.
Hopefully MultiBlog will be able to handle this when you release, then I can drop all those other wannabes :)
Cheers!