Over in the Living Pathfinder forum, you asked the following with the same thread name:
Hey folks wondering if anyone has an idea on how to work up the following items:
(1) a magic potion belt similar to a bandolier and dedicated to potions/poisons only. Something similar to the Haversack in ability but tasked specifically to potions.
(2) gloves for someone with natural weapons/unarmed attack that can change properties (say for instance change from cold iron to adamantine)
Any positive help would be greatly appreciated as i am still learning the item creation rules.
Well, that is a game thread forum, and this is the mechanics thread forum, so I will answer over here. (That game world doesn't have custom crafting.)
The Haversack is already quite useful in that it makes it a move action to retrieve the potion, and it specifically does not provoke and AoO. It has all you need. Now, if you want that crafted in a different shape than a backpack, it is just a matter of having the wizard who enchants the item work with a different form of a bandolier instead. Unfortunately, the spells needed to do the crafting are the same, so the cost is going to be the same. You don't get a discount in cost for having a smaller area available inside the "secret chest" that is on the other end of the magic. It is also a special order item, so (in my game) you would need to find an appropriate enchanter, maybe a master craftsman leather worker, and talk them through the processes of custom crafting the item, and then waiting for it to be completed. That can be a side adventure in and of its self.
Result: Same cost, custom work, may be side adventure to get done.
As to the gloves, the short answer is +3 magic overcomes silver and cold iron, +4 overcomes adamantine. A +4 weapon, of which you would need two, one for each hand, is far more expensive than simply buying weapons of each of the metals and carrying them in your haversack. It is a move action to retrieve, and a standard to equip them. So, you save a ton of gold by wasting only one round to get ready for a fight. If you know ahead of time what you will face, you can save that round by switching before combat.
Because of the vast differences in metal value, I am not seeing anything that can transform one metal into another that would be appropriate. Fabricate requires the finished product to be the same as the raw materials. So, that is out as the base spell for the magic.
You are better off paying for Permanency on Greater Magic Fang, cast by a 16th level mage. Paying him to do it twice, you get +4 on two claws, which will always give you +4 attack and damage, and will bypass all the metal DRs as well as magic. The cost of the spell is tied to material components and not caster level (well, appears that way, but debatable), so it would cost 15,000 gp to get two claws done. That is far cheaper than buying a single +4 weapon at 32,000 gp. Again, the problem is "can you find an appropriate level mage" to do the job. Someone that high of level will be rare and hard to find.