MarkB
Legend
Not having the DMGII, I don't know if I'm duplicating the Item Components concept here, but I'd suggest assigning an appropriate treasure-parcel value to the useful items that can be harvested from the dragon, and then treating them as specialised ritual components which can only be used with item-creation rituals, including Enchant Magic Item, Transfer Enchantment and Brew Potion.
The components can be sold to merchants only for 20% value, but count as 100% value when provided for one of these rituals.
That way, you can characterise their usage in magic items however you want to. If they're being used in the creation or enhancement of magic armour, the ritual caster is incorporating the scales or hide into the armour to grant it extra resilience. If making a weapon more powerful, the blade is being reforged with dragon's blood alloyed into its metal. If brewing potions, certain of the dragon's organs or bodily fluids are being boiled up and incorporated into the recipe to give it added potency.
The results, game-mechanically, are exactly the same as if you'd used normal ritual components, but aesthetically, these items now incorporate aspects of the dragon used to create them.
The components can be sold to merchants only for 20% value, but count as 100% value when provided for one of these rituals.
That way, you can characterise their usage in magic items however you want to. If they're being used in the creation or enhancement of magic armour, the ritual caster is incorporating the scales or hide into the armour to grant it extra resilience. If making a weapon more powerful, the blade is being reforged with dragon's blood alloyed into its metal. If brewing potions, certain of the dragon's organs or bodily fluids are being boiled up and incorporated into the recipe to give it added potency.
The results, game-mechanically, are exactly the same as if you'd used normal ritual components, but aesthetically, these items now incorporate aspects of the dragon used to create them.