Reality check!! Tancredo had nothing to do with the Flight 93 Memorial design. He was appalled when he saw the original crescent and tried to get the architect to change it. As you can see by the Islamofacist shrine link, the architect pulled a fast one in his "redesign".
Direct your comments to the architect and the National Park Service. They are the appropriate contacts.
Does Tancredo support the "re-design"?
As to something memorializing the 4 terrorists? How about a 4 hogs roasting on a spit? Something feeling the heat of an eternal flame to symbolize the 4 terrorist bastards burning in hell.
Maybe a crescent shattered into four flaming pieces dug into the hole where the plane crashed, surrounded by an elevated halo shape made up of glowing glass spheres, one for each of the passengers. It could be called "The Final Destination".