The Adventurer's Vault states that the spiked shield:
can be enchanted as a magic shield or a magic weapon, but not both. A spiked shield enchanted as a magical weapon does not occupy a character's magic item arms slot. (pg.10)
This is unclear about whether it also takes up a "weapons" slot.
Could I wield an enchanted spiked shield on one arm and hold a magical weapon in the respective hand? I'm aware I couldn't attack with the weapon, but it may be useful for its property.
E.g. would a character wearing a rhythm blade spiked shield and holding a quicksilver dagger on the same limb benefit from both their respective properties?