A braggadouche is a person who, through gratuitous and excessive bragging, becomes a douche-bag. "Braggadocio" came from the word "braggadocio" plus "douche-bag". Hence braggadouche.
Mark: Hey look its Gabriel again, all he ever talks about is his lawyer job, downtown condo and new mercedes.
Moe: Yeah, he is such a braggadouche!