http://www.forever-fantasy.net/modules.php?name=News&file=article&sid=688&mode=&order=0&thold=0
If the job listing is real then Tri-ace have two jobs available.
1. Someone to work on the next game in a famous RPG series for the PS3
2. Someone to work on the next game in a famous fantasy RPG series and a new fantasy RPG on the 360.
The only two famous series Tri-ace have are Star Ocean and Valkyrie Profile. I haven't heard anything about the developemnt of VP3 so I think it probably means SO4 is multi.