Looks that way. Barbara did say earlier in this thread (P9) that the game was still being worked on and that Arthur was too busy to post any more information or screenshots. However, Arthur himself promised a hint 'soon', and that was at the end of May last year (P2 of the LDW dying out thread...sorry, I have no idea how to embed links here!)

The Previews page is still promising a new game in 2011 and the progress bar hasn't moved at all. There's been absolutely no updates and no information. I'll keep checking back because I do like LDW games, but as far as the release of the Mystery Game goes, I've now reached the point where I'll believe it when I see it. Shame.