Buying or Crafting a Feat

[Gildedragon]

I am thinking of allowing warforged characters to buy or craft themselves the tracery feats. Any thoughts as to what the purchase cost and craft DC ought to be?
Likewise what would a good cost be to get tracery in other damage-inducing/DR overcoming metals (Cyrite, Mournlode, Darksteel, Kheferu, etc...)

Since these affect 1 attack (slam) the base cost ought to be as getting a weapon of said material.
+ something for their +1 untyped bonus to certain saves. (Let's say a bonus part of the time is a +.5...) Huh. Got it figged out then material cost + 500 gp; craft. DC 12 & DC 20 (simple weapon + masterwork)

[Slipperychicken]

Double the price, because it doesn't occupy a body slot. So that should come out to 3,000gp for Silver and 5,000 for Cold Iron. That actually sounds about right. Maybe make them both 4k?

Depending on how common those other DRs are, maybe give or take 1-2k, but not below 3k if there's also an untyped save bonus in there.