Is it time for a mega-mashup of two of the U.S.' top tobacco producers? It just may be. With shares gaining more than 45% over the last 12 months and nearly 30% so far this year, Lorillard is looking like a potential target to Reynolds American. The stock could soar more if the two companies agree to a buyout making Lorillard Monday's Chart of the Day.If they can settle on a price, the merged entities could face antitrust issues, and may have to divest some businesses to satisfy regulators. And with a price tag likely to exceed $25 billion, synergies between the North Carolina-based companies would need to be found quickly.