Not really a plugin, more like a workaround (for now).
This is a windows live contact editor I recompiled from http://www.codeplex.com/Contacts and made it so it can accept command line arguements:
a) Download http://dl.getdropbox.com/.../400763/ContactViewer.zip - I think you'll also need .net 3 for this..
b) Decompress it anywhere you want
c) Go to your Windows Live Messenger options -> Security and uncheck the contact storage checkbox (encrypt....)
d) Associate your .Contact files with contactviewer.exe
e) Add this folder to your FARR folders: yourprofiledir\Contacts\firstname.lastname@example.org (look for it first) and make it so it searches for all .contact files
f) Find a contact in FARR and press enter