Cadillac is back in the race to be the best-selling automotive luxury brand, just a year after it appeared that imports such as Lexus and Mercedes-Benz had a lock on the position for the foreseeable future. The surprisingly close battle is because of Americans' fondness for what once would have been considered an oxymoron -- luxury trucks. A factor only since 1998, they've quickly moved from the outskirts to the luxury mainstream, helping boost some brands. The spread between number one luxury brand Mercedes-Benz and No. 4 Cadillac was just 7,075 sales through October, according to industry tracker Autodata. Through October, Mercedes sold 169,133 vehicles; Lexus, 166,992; Lincoln, 165,146; Cadillac, 162,058, Autodata reports. BMW, once a niche brand, is a respectable No. 5 at 151,152. It will be a larger factor if its new South Carolina factory can build more of the popular X5 sport-utility vehicles.