How about an item or block you can place down and hold the use key on, and it will bring up a menu saying something like “Upgrade all pillars to (wood)(stone)(scrap metal)(armored)” and “Upgrade all foundations and floors to (wood)(stone)(scrap metal)(armored)”? It can have a display on how much wood, stone, scrap metal, or high quality metal required to use.
It would be very useful for building larger bases. Upgrading a billion pillars can get super tedious and quite annoying. same with really any other item.
edit: Only exploit I saw so far was having a raider upgrade from stone to scrap metal, so they can blast in easier. Maybe the item could have low hp, or can only be used when you have access to all tool cupboards.
https://www.reddit.com/r/playrust/comments/3hp1f9/new_convenient_building_itemblock/ Reddit thread discussing same topic.