The two US based plug and play arenas are in Houston and Kansas City. Both could and would support hockey, but you would lose a billion dollars in potential expansion fees especially in Houston.
Portland would be an option, but I don't know about the interest there.
Quebec is the obvious Canadian based plug and play arena, but the lack of a corporate base wouldn't help the bottom line.
Although filling up the arena with fans would be no problem unless the owners price them out of range.
Quebec might be better off waiting for Atlanta to fail for a third time.