Double, triple-column posting?

I’d like to use Thematic in a more CMS way by having posts “tombstoned” beside one another. I keep finding solutions that hit around the issue, but not what I’m wanting. Simply put, I’d like to have posts of certain categories to be (e.g. in a double column layout) to appear beside the primary column with its posts. I’ve seen many examples of putting various bits and pieces of posts in a sidebar, but they were always just glorified “recent posts” style handling. I’d really want to put the entire post in a sidebar alongside the main column where they usually appear. Is this possible with WP/Thematic, or should I look to a more CMS-oriented package?