bdew-minecraft/neiaddons#32

I really would love to see this get made! I need it for the IC2 Fluid Nuclear Reactor!
It would be helpful in other mods like Railcraft - using it with Loaders and Unloaders. It would be nice to be able to place items in specific slots in rail-carts and retrieve items from specific slots too.

Agreed. It would also be insanely useful for building fully automated setups with Factorization ore processing.

I'm closing this issue as part of a spring cleaning of my issue trackers from old stuff.

If you believe it's a bug that is still relevant in Minecraft 1.12 - Feel free to reopen it.