Who wins? One thing is for sure, this wouldn't be like the Clay fight - Holmes didn't have Ali's physical gifts to overwhelm Sonny (plus, Sonny wasn't at his absolute peak by time he fought Clay).
Also, unlike many remember, Clay-Liston was near even at the time of stoppage. Clay made Liston look stupid but didn't land that many punches, apart from rounds 3 and 6. That said, I take Holmes. Good jabs troubled him and few fighters ever had as good as Liston so it would be a hard fight early. Liston however usually steamrolled smaller guys, but Larry was the larger guy and had the better stamina. Holmes by UD in a fight where he sweeps the late rounds to secure his victory