various post templates

Hi,

I need several posts to be a little bit different than the usual ones.
so all posts will use the default post look and feel, but a few should have something a little different (a black ribbon on the right hand side as it is for a memory of a person recently deceased).
Is that even possible? I need the change of look and feel to be both on main page with all the excerpts and also in the full post page.

Your thoughts on the matter are greatly appreciated.

Kind regards,
Tomarsh