Baten Kaitos 1&2 were apparently made by Tri-Crescendo (a splitoff from the frequent Enix-ally, Tri-Ace), under the directions of Monolith (a company that split from Square and joined Namco).
Tri-Crescendo is just finishing up work on Baten Kaitos 2 (which Nintendo apparently took over from Namco) and Valkyrie Profile Silmeria for Enix on the PS2. Next they're working on an Xbox360 RPG for Namco called "Trusty Bell".
Monolith is ending the Xenosaga series after #3, and yeah, they're apparently working on Disaster: Day of Crisis for the Wii next, apparently without any involvement from Namco. There are rumors saying that maybe Namco/Bandai sold whatever hold they had on Monolith to Nintendo, possibly in exchange for the chunk of Bandai that Nintendo owned, because a Nintendo rep said that one of Nintendo's second parties was making Disaster.
There are a whole bunch of "Tales" teams, but it's hard to tell which ones are working on what. Right now they're working on Tales of the Tempest for the DS, a full Tales of Destiny 1 remake for the PS2, a Tales of the World game for the PSP, a Tales of Destiny 2 port for the PSP (not to be confused with the Tales of Eternia port already on the PSP, which was called Tales of Destiny 2 in America), and a Tales of Symphonia (PSX version) port for the PSP. I'm probably missing some more.
If this rumor has any weight to it, there's nothing stopping Namco from making/hiring a new team (especially if they've lost Monolith), and/or declaring them to be yet another "Tales" team.