Layton could be on the verge of being officially announced for North America.
Professor Layton and the Miracle Mask has been trademarked in the United States. The Nintendo 3DS title, which was a launch title for the 3DS in Japan and previously announced for Europe, has not been formally announced for the region.
However, last year, Professor Layton and the Last Specter was trademarked in the United States and then announced at E3 shortly thereafter. It can be expected that Professor Layton and the Miracle Mask will follow a similar trend, and be announced soon.
For more information about Professor Layton and the Miracle Mask, feel free to check out my impressions with the Japanese version.