This may be too loose of an interpretation for some though, and it shoehorns you into a specific magic weapon with a property that does nothing for you even if you multiclass. You do get the dwarven weapon training benefit bonus to implement damage rolls though.
One thing I did with an Artificer was take Arcane Implement Proficiency: Pact Hammer because a Pact Hammer is "a kind of implement associated with any arcane class other than your own." I did it so that my dwarf could use a mordenkrad with the Daily 'Dancing Weapon' alongside implement powers.
Of course, I would simply let you use the hammer as an implement anyway. While I love the 4E Bard, I hate the implement/weapon divide for them. It's especially bad for the Prescient Bard, which requires Songbows as a patch to make them playable.