Generic "Reach" related question, purely because you obviously went neck deep in the code:

Can this kind of Lua "trick" be used to say, allow "extra Reach" BUT for only a list of items WHILE being held?

As in, everyone has normal reach BUT if they are holding "concrete bricks" they get a ton of reach? This would stop people from abusing Turret Creeping, while still allowing people to place concrete around a base without having to walk 1000 miles to do it.

Don't really understand Factorio Lua code and I was trying to figure it out from what you had.

Yes, definitely! That’s what this mod does when you are holding wires, and cargo ships does it when you are holding waterways.

The tricky bit is preventing you from control-clicking the items into chests at any distance. For this, I put the player into a different permissions group whilst the range is extended. This approach doesn’t scale well if another mod were to use the same system, so I’ll be adding an interface soon so that other mods can control which items Remote Configuration gives infinite range for.