Marrowmelding (3.5e Trait)
From D&D Wiki
 Marrowmelding [General Trait]
The character gains the ability to creates functional items out of bones she encounters throughout her adventures. For each piece of marrowmeld the character is using she gains a +2 on all intimidate rolls.
Prerequisite: Medium or Heavy Armor Proficency
Benefit: The character forgoes an armor proficency and instead masters the ancient art of marrowmeld, she is able to fuse bone matter together in such a way that she creates armor, weapons, or other tools. Any armor created by marrowmelding has an armor bonus equal to a normal piece of armor of that type, plus the constitution modifier of the creature used to create it. If weapons are created they deal damage equal to a normal weapon of that type plus the strength modifier of the creature used to create it. All other characteristics of the armor are equivalent to the standards put forth on the D&D wiki. All items created are equivalent in size or smaller than the creature they come from. For example a medium-sized breastplate made from tiger bone (Constitution of 17, +3) will have an armor bonus of +8 it will weigh 30lbs with a hardness of 10, 25 hit points and an arcane spell failure of 25%.
Drawback: The character must choose to forgoe gaining an armor proficency in order to gain marrowmelding. Moreover as the character is wearing mystically fused bones she takes a -2 on diplomacy rolls for each piece of marrowmeld she is using.
Roleplaying Ideas: A character on campaign who has no armor or weapons, or whoose equipment is broken can easily make new equipment as long as a supply of bone is easily accessible.