Cleon
Legend
Damage Reduction: The weredrake's hybrid form has any damage reduction possessed by the base dragon.
Come to think of it, FR7's New Lycanthropes have "90% of new lycanthropic species can only be harmed by silver or magical weapons of +1 or greater." Meaning most of them have the standard weapon-resistance of an AD&D Lycanthrope.
I'll change the proposal to:
Damage Reduction (Ex): A weredrake in animal or hybrid form has damage reduction 10/silver plus any damage reduction possessed by the base dragon. Multiple damage reductions granted by the weredrake template never stack. Thus, if the base dragon has DR 5/magic the weredrake has DR 5/magic and DR 10/silver (meaning its damage reduction reduces the damage from non-silvered magic weapons by 5 points, non-magical silver weapons by 10 points, and all other weapons by 15 points) instead of DR 15/silver and magic or the like. Should the base dragon also have damage reduction that ignores silver, the weredrake has DR 10/silver or the base dragon's DR/silver, whichever is higher.
A few weredrakes (no more than one in ten) have damage reduction that is vulnerable to a different material than silver; for example its damage reduction could ignore cold iron, obsidian, bronze, jade, electrum or gold.
Alternative Option:
Some weredrakes are vulnerable to enchanted weapons and have damage reduction 10/silver or magic instead of DR 10/silver. The proportion of these is as the DM's discretion, from one in ten to 90% or more of the all weredrakes.
A few weredrakes (no more than one in ten) have damage reduction that is vulnerable to a different material than silver; for example its damage reduction could ignore cold iron, obsidian, bronze, jade, electrum or gold. If the weredrake is also vulnerable to enchanted weapons as per the previous paragraph its damage reduction is modified accordingly (i.e. "DR/gold or magic" instead of "DR/silver or magic").