I just took my Warforged wizard to Forgotten Realms. None of the villagers seemed surprised to see a sentient golem walking around. Now that it has been established that extraplanar travel is a reality, I would like my Warforged wizard to visit some other classic campaign settings. (Yes I know these are not D&D, just classic TSR)
Gamma World - Can you imagine a WF sorc joining The Created to exterminate Pure-strain Humans? How about my WF debating life's deeper meaning with a Thinktank? Vibro-blade anyone? Would the living part of my WF start to mutate when exposed to all that radiation? What incredible powers could he attain, and how would all that ancient ultra tech interact with my magic?
Boot Hill - Finger of Death on Doc Holiday. Charm animal would make it so easy to rob a stage. Which would win, Gattling gun or magic missile?
Top Secret - Join the Directorate of Extraction; use wraith form to bypass the most sophisticated security systems. Charm person is perfect for interrogations and infiltration. You get the picture.
Why be limited to Eberron anymore?