The Wanamingo Queen is larger than other Wanamingos and silver. While Wanamingos were going to appear in Fallout 3, the queen must not of, because there is no hidden game files for the Queen. However, someone might be able to mod in a queen, by making the Wanamingo bigger, and coloring it silver.
The Wanamingo Queen can't be found any where in Fallout 3. It is from Fallout 2, and possibly would of appeared in Fallout 3 if the Wanamingos stayed in the final cut.