Itemization towards late game

I think it would be nice to have extra slots that are used for pieces of items until we get 6 full items, with one or two being the limit. Like, late game I have one spot left and my item requires 3-4 pieces but I have to buy it in bulk because I have no room to build it. Now sure, it's not that big of a deal and you can get gold faster late game, but sometimes I want to buy the lifesteal portion of an item but have to wait until I can afford the whole thing because I bought the damage portion first.

Once the 6th item is complete, the extra slots would disappear.