Psikerlord#
Explorer
I love this idea, and would also consider things like putting a one shot pistol built into a cane, a poison dropper attached to the bttom of a tankard, etc - rough rules for which are in DMGItem combos work really well. Like a dagger that extends to a sword, or a healing kit with a hidden grappling hook. It feels neat theme wise, but it's not all that powerful to be able to carry two items in a single item.
You could add in an ability to just combine two items for a cost of gold with the benefit of a slightly faster switch over and maybe some overall weight reduction.