MU blog aggregation, doable?

I have an 3.5 WPMU install and need to automatically post new posts/updates etc to say twitter and other sites.

Most of the plugins out there seem to allow individual site owners to do this but I would like all sub-site posts to be auto posted.

I was thinking that perhaps the simplest solution might be to aggregate all of the posts then use one single account on twitter and others to post updates to.

I have seen other posts on this topic but none that seem to fit what I am needing or where I can just jump in without hijacking.

Anyone have any thoughts on this? I’m sure I am not the only one who has ever needed this.

Thanks.