New around here, but I was reading through this thread and I have a suggestion regarding quivers, scabbards, slings and holsters. Why not make it so that holsters and scabbards are modifications to the weapons they would hold themselves. That way these non-container containers reduce the volume in your inventory the weapon takes up and reduces the move cost of drawing/stowing the item modified by the scabbard/holster. The distinct difference would be that the item only gets the volume reduction for some items if they are wearing a belted item on the body part associated with the mod, waist belts for hip holsters and scabbards. Rifles and crossbows modified with slings would take up significantly less volume and wouldn’t require a belted item to gain the benefit. I feel this is balanced by the fact that many rifles are heavy and were you to modify several rifles with straps and carry them, you would quickly reach your weight limit. If this needed to be balanced a bit, you could make it so strapped rifles provide an encumbrance penalty to the torso if you carry more than one sling-modified item in your inventory at a time (not wielded) The same could apply to the belted volume reduction mods: if you carry a belt-held holstered pistol and a belt-scabbard modified sword, you get an encumbrance penalty for overloading your torso slot. Consequently, a boot-sheath modified knife (legs/feet) and a shoulder holster (arms) would not apply an encumbrance penalty.
If you want to remove a LBE (load-bearing equipment) modification from a weapon, you simply Disassemble it, it will give you the weapon back with the LBE mod, which you can apply to something else. There should be little to no room for component loss on disassembly of an LBE-modified weapon. Turning quivers and scabbards and such into weapon mods seems like a more elegant solution to volume reduction in specific weapons than to create a system to modify your own gear. Most often a holster or scabbard is associated with only one weapon in that gear’s lifetime. A modification such as this might be relatively simple compared to a total change in storage gear behavior. Keep in mind that LBE mods increase the weight associated with the weapon while reducing it’s effective volume. The holsters or scabbards might also provide a protective buffer for a weapon. For instance, if an effect were to damage your pistol, it would damage the holster first before damaging the pistol.