In a couple threads in the general forum, Neilo and Chowdown joked that the pewter Rook figurine that comes with the collector's edition provides +800 Health and -35% to ability cooldowns.
While those exact stats might be a bit overkill (as it's essentiall a supercharged Staff of Renewal with tons of extra HP instead of fringe benefits to HP and MP), why not actually have this as an item?
It could be a favor item, perhaps with stats that would be beneficial to Rook.
+40% Mana Per Second
-15% to ability cooldowns
Make it cost something like twenty thousand favor points, and auto-unlock it for everyone who's registered a collector's edition because they have the real thing and because they're still waiting for that MyColors desktop theme.