[Kryptonite]

The monsters in the abyss appear to drop all varieties of runecrafting pouches regardless of your runecrafting level.

Also, it seems you are able to obtain multiple of the same size of pouch. I've only been able to test this with the large pouch so far. I believe I got another drop for the small pouch and the game didn't allow me to pick it up because "you can only have one of each type of pouch". I know I was able to pick up multiple large pouches, but they were all in different trips, so I'm not sure if it was only because I didn't have the pouch in my inventory or not.

I do not yet know if I can actually use multiple large pouches at once since I don't yet have 50 runecrafting, but I'll post an update when that day comes.

[Muse]

I also managed to have multiple medium pouches in my inv, when i filled one with p ess the other pouches seem to be connected to that one and have status of filled.

Also if your pouch gets damaged and you drop it to get new one fresh pouch will degrade after first sometimes second time after filling.

EDITED: excuse mua.. NEVERMIND! Just realised i can repair the damaged pouches at Dark Mage in the Abyss 
I wasn't really runecrafting much so forgive me!