I would say Wang Xiang from Youth Gone Wild, but I think you've already read it I think you may like 1/2 Prince, the main character is a bit cocky, I guess. If you liked Ouran, you may also like Millennium Snow, one of the characters is a bit like Tamaki. Tsukasa from Tokyo Crazy Paradise is a bit like this, too.
The lead from Kami nomi zo Shiru Sekai He's kinda cocky in the fact that he prefers "2d girls" over "real females". And even goes to rub in the Hows and Whys. What's funny though... is how he's kinda delusional about his love of 2d girls.