[filiadragongurl]

Well... The best friend of the main character in Card Captor Sakura is "Tomoyo" which I believe is purposely meant to be like "tomodachi yo"... I suppose you could use that^_^;

Or there's Aibou (which I think they already named a robot companion dog made in Japan) which according to jim breen's dictionary is: 合い棒 【あいぼう】 (n) companion