A middle-aged male,typically from a small town in the American south or midwest,who grew up in the 40s,50s,or early 60s,uses about a quart of Brylcreem or Vitalis to slick his hair into a 6-inch pompadour,wears his pants 3 sizes too tight with a massive beer-&-fried-chicken gut hanging out,is waaay too politically conservative,and typically drives a giant, rusty,early-70s Chevy,Ford,or Lincoln and listens to classic-country & rockabilly.Usually accompanied by a female with a beehive and tons of red lipstick.
"Look at that old dude that just got out of the '71 rustbucket Impala,what a Dead Elvis!"
Something that was bound to make it big,like in Vegas, but failed.
How about that ad-agency? Nah, that was just a Dead Elvis.