Oh man, I feel a bit bad for not replying sooner when you've given such a thorough response! The Wolf Among Us and Doctor Dekker's Insanity Party ( or whatever ;) ) look pretty awesome.
In fact, far better than what we can hope to do on a budget of a few hundred quid so. As ever- we need to concentrate on squeezing every pound and penny- and playing to our strengths (dialogue, story-telling, puzzles etc.).
Can you think of any really crap detective games to give us reverse inspiration- as in- "oh wow, we can do better than that"? ;) I'll start- The Agatha Christie ABC Murders on NDS- which opens with a maths problem...