http://www.newvegasnexus.com/downloads/file.php?id=34931Try it out if you dare.
You could look into making an activation perk (perk that lets you change the default behavior of activating certain objects without actually modding those objects). Then add a quest script that automatically shoves items into your bags during GameMode (so it doesn't happen while in MenuMode, ie while you're crafting).
That's a possibility. The auto harvesting like in TES games is a bit script intensive, but that should be less so. It would be a bit of work to set up though.

Question: How did you make it so the bag weighs as much as the stuff in it? Specifically, how'd you make it so you can even detect how much stuff is in the bag? (and how'd you set the weight of the bag - used a token item or something?)
It doesn't really set the bag's weight. It gets the player's inventory weight before and after using the bag and sets a global for its weight. It then mods the player's inventory weight when it gets picked up.