Professor Layton 4 includes unlockable Professor Layton RPG

Most American gamers have yet to get their copies of Professor Layton and the Diabolical Box, and Level-5 has already released news that will make you yearn for the fourth game. At last night's LEVEL-5 VISION conference, the company announced that Professor Layton and the Devil's Flute will include a bonus game, Professor Layton and London Life.

The Brownie Brown-developed London Life is an RPG that, according to Level-5's Akihiro Hino, will last over 100 hours. It was originally announced for the ROID cell phone game service — we have yet to learn whether it will still be released there in addition to DS. Devil's Flute will be out on November 26 in Japan.