In an interview with Famitsu between Ace Attorney movie director and Takumi (Ace Attorney dev), he commented briefly on the status of Professor Layton vs. Ace Attorney.
Takumi said “Production on Layton vs Ace Attorney is at its climax. It’s like my entire life is focused on it. While I still can’t say much, it’s progressing well, so please wait a bit more.”
“While [Latyon vs Ace Attorney] is being developed jointly with Level-5, games are my job, so I can’t just leave it to someone else like with the movie.”
Good to hear, I’m very excited for the game!