We already have multiple kit champions, why not multiple kit items?
TLDR: More expensive multi-kit items could provide champions with much needed flexibility while adding an interesting dynamic to the game.
Currently, there's a handful of multi-kit champions:

They've all added some interesting dynamics to gameplay. This got me thinking, we have multi-kit champions, why not multi-kit items? After all, we already currently have enchantments to create multiple end builds for some items that can be switched easily.
These would be more expensive than their normal item counterparts and may not be as gold efficient, but would grant much more flexibility in gameplay. They would not have "actives" but rather would allow a switching of forms with different stats/passives that would allow for certain uses in certain situations. It could also grant a little bit more utility to champs who need it and make support play a lot more interesting.
We'll start off with a pretty basic example.
Doran's Loadout
Recipe:
+
+ 320 =1200 gold total cost
Stats-
+150 Health
+10 AD
+5% Lifesteal
Unique Passive: Defense Stance : Blocks 15 damage from all incoming enemy champion attacks/spells. Regenerates 8 health every 5 seconds. Switchable to (60s cooldown): Unique Passive: Offensive Stance : Grants the user 10 bonus attack damage and 5 Armor Penetration.
This adds a bit of interesting dynamics for all AD champions. You can either go temporarily tanky or get an attack buff. Is your jungler coming to gank? Maybe switch to the offensive stance. Their jungler ganking you? Swap to defensive stance.
A bit of a more late game one:
Icebane
Recipe:
+
+
+165 gold = 2400g
Stats:
+300 Health
+35 AD
Unique Passive: Stay Warm : Reduces the effect of all slows by 25%. Switchable to (90s cooldown): Unique Passive: Immolate : Auto-attacks deal an additional 10+(1 per champion level) magic damage on hit.
This one might be useful for an adc or bruiser who's having trouble with being kited.
Here's one for mages:
Angelic Staff
Recipe:
+
+ 240 = 2000g
Stats- +40 AP +25 MR +25% Base Mana Regen
Unique Passive: Mana Font: Regenerates 2% of missing mana every 5 seconds. Increases the Base Mana Regen from base item to +100%. Switchable to (90s): Unique Passive: Casting Time: Grants a +10 AP bonus and +5 magic pen and reduces the cooldowns of all spells by 1s.
The items themselves are subject to tweaking/overhaul, it's more the concept that I'm interested in. An idea that creates another layer of flexibility and strategy within league.
Thoughts?