1 bug and 1 suggestion left in my mind, it's working fine on my site now besides that.
The bug: Only the gray buddyicon is showing, the other 2 colours are not showing, there is just a blank space where they are meant to be. The conditional doesn't seem to be working for my site.
The Suggestion: Make a link from the postbit to the persons buddy page. I know it's simply and I could quite easily do that myself for my forum, but it would be a good way to give extra coverage of the feature.
Besides that, I think this is a great feature and it makes great use of the buddy list, which for the most part I reckon is unused on most forums.