Are there any buildings that allow you to store trained troops in it, of which will then be used to defend your base if someone attacks?
There's another game that offers a similar mechanic, from Backyard Monsters, called a "Monster Bunker", where players can spend 'Putty' (a resource currency) to store created troops to defend the base, and are killed off if killed while defending.
Wiki page: http://backyardmonsters.wikia.com/wiki/Monster_Bunker
Does Clash of Clans have a mechanic like this? one that allows players to store their own troops as defense?
Or are clan troop donations (which are stored in the Clan Castle) the closest thing to this?