Project X Zone features characters from Namco, Capcom, and Sega into a SRPG known as Project X Zone and Namco is localizing it in America, Australia and Europe. It will be released in Summer 2013 with Japanese voices only.
On the Namco side, you have characters from Tekken, God Eater, Xenosaga, .hack, Tales of Vesperia, Namco x Capcom, Yumeria, and others.
Sega has characters from Resonance of Fate, Valkyria Chronicles III, Space Channel 5, Fighting Vipers, Sakura Wars, Virtua Fighter, and others.
Capcom has characters from Rival Schools, Megaman, Resident Evil, Darkstalkers, Devil May Cry(original I believe not the new one), Dead Rising, Street Fighter, and others.