Craft magical supplies

[Spuddles]

Other than making enemies and losing friends, is there anything preventing taking craft: magical supplies to reduce the cost of magic items by 2/3?

Same trick, but with spell components?

[docnessuno]

Craft Magic Arms And Armor [Item Creation]
You can create any magic weapon, armor, or shield whose prerequisites you meet. Enhancing a weapon, suit of armor, or shield takes one day for each 1,000 gp in the price of its magical features. To enhance a weapon, suit of armor, or shield, you must spend 1/25 of its features’ total price in XP and use up raw materials costing one-half of this total price.

Raw matierials are obviously not the product of any craft skill.
Other item creation feats use the same wording.

[TuggyNE]

Same trick, but with spell components?

I wouldn't be terribly surprised: spell component pricing is absurdly ill-thought-out. (For example, if the market for diamonds changes, you suddenly need a different quantity for resurrection.)