For those w/o Wardrobe...
Use:
/equipslot # Item Name
# here is the number assigned to a specific equipment slots. The equipment slot #'s start at the helm and move sequentially down, skip the weapons, and continue at gloves. The weapon/shield slots are numbered last and are something like 14, 15, 16...can't recall exactly the specific numbering scheme so test it out.
Example:
/equipslot 1 Fancy Hat of Spirit
/equipslot 2 Spiffy Necklace of Evocation
/equipslot 15 Owlish Staff of Spirit
I'm not at home so I can't test these out but I think that's what I used on my pally to switch from sword/board to twohander in a click.