Doubly-compound leaf examples?
Albizia julibrissin (Persian silk tree) is doubly compound (AKA bipinnate) and has a conspicuous pink/white fluffy flower. This tree is an Asian native, but it's a commonly cultivated (and equally commonly escaped) plant in the U. S. You should be able to find it in numerous locations. Look in yards and along roads. 


http://www.missouriplants.com/Pinkalt/Albizia_julibrissin_plant.jpg

For native species: Gleditsia triacanthos (honeylocust) is a fairly widespread (though uncommon) example of bipinnate leaves. Here is an image from Will Cook's wonderful website: