There is a concept that Orcs were once Elves, but were altered (usually twisted by magical means or descended into depravity).
In the same vein, I do think it would be interesting to have the "same" races in all the worlds. Have Eladrin in the Industrial Plane, Elves in the Natural Plane and Drow in the Shadow plane. But not all races come in three parts like that, or can be grouped into similar relationships.
If we were to have all the races descended from a handful, what would the original races be?