Working on it, some problems with LinkedIns new API has put a 3 month speed bump in front of me. Now that the new API I needed is implemented; it doesn't work with their latest release.
It is not clear yet if we will be making this a standalone plugin or not. All integrations I develop such as these go into CB Connect, an incubator project, and we then decide if I should make them individual plugins. It's likely we will as they do offer a PHP library as apposed to my OpenSocial usage with CB Connect.
Sorry, no idea when CB Connect will have linkedin support. I was hoping for today, but that won't happen due to API issues. Shooting for this week, but no guarantee.