My character has invested in the Smithy skill, and I want to outfit my whole party with Elite Plate. I'm playing a dwarf and I took Magnus' leather armor to make my own set of the chainmail you need in order to craft the Elite Plate. But now I can't for the life of me find another small leather armor in order to make a set for Magnus. I've looked in every shop in Shrouded Hills, Black Root, Dernholm, and Tarant a number of times with no luck. Does anyone know a place I can definitely find some? It's annoying to have the rest of the party well-armored and to have Magnus running around in a Small Guard's Leather (which you can't use for crafting by the way.)

While I'm on the subject, is it possible to craft an Elite Plate for a half-ogre (I'm thinking Chukka)? And if so, similar question: where would I get the large leather armor? I've seen a few sets of large guard's leather, but no regular leather.

sorry at the top of my head i cant remember the place but i found 2 high end armours doing the main quests

Small Leather armour is hard to find in stores. There's only a 20% chance to find it in Castleton's General Store in Tarant, and 10% in general stores elsewhere. In the smiths in Shrouded Hills, Black Root, Roseborough, Dernholm and Stillwater, there's a 15% chance. These same places also has Large Leather Armour, but there's only a 10% chance. You have to be at least 3 screens away from the shop at midnight for it to restock. Good luck (literally)!

A guaranteed drop (I think) for Small Leather Armor are the thieves on the outskirts of Black Root. I'm fairly sure at least one of them is a dwarf - might be two. They're quest-related though, so you'll want to pick up the quest first.

Large Leather Armor can be found from another band of thieves - the ones holding the bridge out of Shrouded Hills.
I don't know how you solved that quest, but my standard solution no matter what character I play, is to pick up Sogg Mead Mug, beat the shit out of the thieves and equip Sogg with their Large Leather Armor. Virgil and a well equipped Sogg Mead Mug makes for a really good starting party.