Don't flame me too hard. This is just an idea I had the other day.
I was thinking that these two items could work well together in PvP for some nice burst damage, especially as an Unholy DK. Based off of what i'm reading on Wowhead this would work especially well for Unholy DKs that use Ebon Plague and Black Ice, as both effects deal Shadow damage. It would be a lot of fun in battlegrounds at the very least.
Think this would work?