Bootboy, Am. hornbeam(Carpinus caroliniana) and Hophornbeam(Ostrya virginiana) are two woods with two different bow building characteristics with HHB being the best. Hornbeam will make a bow but I've heard it's not all that good(no personal experience).
I have plans to build a straight limbed sinew backed bow. Jay Massey has always been one of my archery heroes so I thought I'd copy one of his osage bow designs but sinew backed HHB would probably be a great combo as well.