limit to only one recent post per (distinct) post author?

basically, i want to pull the recents posts, limited by only per author (a cross between this and the blog directory includes recent post/permalink plus avatar). (12 recent posts across network, but if only 7 authors, i would only see 7 posts)

(i don't have access to this site's phpmyadmin to look at the tables, but it's my understanding that the blogs table doesn't pull any other information besides blog name and id.

if that's the case is there a way to query a distinct post author from the site_posts table created by the post indexer and join with another table or something?

if so, could someone please advise how i would edit recent global widget code
$query = "SELECT * FROM " . $wpdb->base_prefix . "site_posts WHERE blog_id != '1' ORDER BY post_published_stamp DESC LIMIT

to achieve that?