Hotel Dusk's sequel, Last Window: Midnight Promise is real and here's a whole bunch of screens to prove it. A while ago, a listing and box art for the Nintendo DS game were spotted on Japanese retail sites.
No word still on a US release, but Japan will see the game soon enough. Enjoy!
アパートに隠された二つの過去とは？ DS用アドベンチャー「ラストウィンドウ 真夜中の約束」が2010年1月14日発売 [4Gamer]