I've already modded the game to replace all the Amulets of Power they patched out, but how might one accomplish this feat?
First you need to have Cheat Engine installed. Then you need the script attached to this post. You'll want to load Cheat Engine and the script once you have loaded your save game. You'll want to enable the options: "Infinite Potions & Free Crafting [num2]" & "Infinite Shop Supply [num3]". Now you can go to any shop. For the Ring of Master Studies you'll want to have a ring that you can sell to the shop owner. At this point you'll want to enable the "Shop Item Editor" option in Cheat Engine. Sell the ring to the shop owner. Now you will want to go to the "Buy Back" tab and buy back the ring you sold to the merchant 3 times, one at a time. on the third time the multiple buy window should open, just buy 1.
After doing this you should see that the Item Type property that previously had a value of just three question marks in the "Shop Item Editor" now has an actual item name value. You'll want to close the shop's purchasing screen at this point. You'll want to enable the "Change" option under the "Shop Item Editor" and put the following ID in the box that pops up: DA3/Equipment/Items/Accessories/Rings/equip_acc_ring_dlc_msft
Make sure there are no spaces in front of DA3, and none after msft, it will cause the lookup operations to fail. If this is successful you should see a message that says a given value has been changed to another given value. After this you will want to open up the store again and you will notice that one of the 3 rings of the same kind you purchased that now reside in your inventory has a different resale value than the other two. You want to sell this one to the merchant. Go back to the "Buy Back" tab again and you will see the Ring of Master Studies now listed in the buy back list. You will want to purchase that ring 3 times, one at a time.. The reason for this is that the first one will always be a damaged copy. The second one might be the correct one, or it might be trash. But, the third copy will actually be the correct item with the correct values and description. You can sell the other two retarded copies back to the shop owner since all they will do is junk up your inventory.
That's it. Congrats, you now have a copy of an item that should be xbox exclusive on your PC copy of Dragon Age: Inquisition. Exit the shop screen and deactivate the "Shop Item Editor" option in Cheat Engine, and you are good to go.
You would follow the exact same procedure with an amulet for the Amulet of Master Studies, using the following value for the Change window: DA3/Equipment/Items/Accessories/Amulets/equip_acc_amulet_dlc_ability_point_msft
This method should work for any given item you want to substitute in as long as the base item you are using for the trick is the same. For example, if you want a ring, you have to start with a ring, etc...
Have fun.