Basic containers

I see that there's items like Scroll or Map Cases, pouches, sacks and such, and then there's Backpacks, Handy Haversacks, Bags of Holding etc.  but only some of these actually allow you to show what has been put into it.  Would it be possible to either expand this feature to all items with the "Container" tag, or allow the creation of custom containers, such as hidden bags, money belts, or even containers that are not carried by a character, such as saddlebags on your horse, your home back at the village, or in a hidden cache?  

Also, if there could be a way to keep track weight within the item along with on the character, to make sure you're not overloading a bag of holding on accident?  Thanks!