Not having played a fleshie yet in over 2 years I'm not sure of the advantages of the so called dragon marks. However having an enhancement line available to all but the noble race seems down right rude to me. Is the offer of a one time feat exchange at a reduced price just compensation?

If we can't get the dragon mark how about something unique to Warforged.

Use the already present game mechanics for the dragon marks. Allow warforged to manifest "signature of the craftsman". Unigue markings that allow us to manifest unique abilities.

Mark of the craftsman- this mark reflects the extra care that some war masters used in creating their constructs.Do to the precison of fit and finish adds +1 to AC +1 to dex and a stackable DR 1

Mark of the Thinker- this mark reflects the knowledge thirst of certain makers. +1 bonus to int. Allows the use of scroll regardless of class

Mark of the Faithful- The god fearing makers piousness is transfered to all of their creations. +1 bonus to wis and chr. +1 holy added to all attacks

Mark of the Scout- Transfered to the warforged by those who need to gather information. stackable 15% striding 10% blurr +5 to hide and sneak skills.

Mark of the Ambassador- Created to assist those who negioate and try to avoid conflict. -2 to attack +4 Stackable to AC. +1 to chr +10 to haggle

Just some ideas. Have at it!