How best to showcase posts across a WPMU installation?

I'm starting to get some great activity on a WPMU installation, and am now trying to figure out the best way to showcase or feature select posts on some of the blogs. I've looked at the "featured posts" plugin, but that doesn't seem to do what I need.

Ideally, I just need a way to flag a post on one of the blogs as "featured" so it will show up somehow in the appropriate section of the main blog. Something similar to the Drupal "promote to front page" flag, on a sitewide basis.

Any ideas? Have I missed something obvious?

I suppose another option would be to write a blog post on the main blog referencing a post in a user's blog, with a link to it...