Figured you would be busy but, well you know how it is, when your a spokesmen for a said Idea you tend to push when someone says something vaguely familiar to the subject at hand..
That said we are using a feat/ skill based Great Detective Prestige Class that is heavy on Intelligence and Wisdom based skills. For them Deduction is a Class Ability for everyone else its a feat.
New skill called observation ( which may or may not be put into the book based on some arguements over spot, and search checks) But I would like to see it there because A) it allows the character to notice small little things that add up to crime solvers.
And I like the compiled abilities of two complicated and over used skills into one that is more specific but gets the idea across
Observation (Int)
Use this skill to make observations about a variety of minuscule things that can come together to form the basis of a hunch. Things that can be noticed are the state of a subjects clothes, lingering smells, a subjects level of nervousness.
Check: The Observation skill is mainly used to detect minuscule things that are unusual about a single person. Specifically mud on shoes, mismatched gloves, missing buttons, and other such things that may give a clue as to the perpetrator of the current case. This skill replaces Spot when trying to determine if a character is in disguise. ( See the Disguise skill in the PHB) By succeeding at a skill check (DC 10) and the character spending time observing a subject can determine the nature of the subject, whether he/ she is out of place, whether the subject is calm, or nervous. With a successful skill check (DC 15) the character can tell what type of occupation a subject has. Obvious occupations such as Sailor, Miners, lamplighters, Musicians, and others that leave obvious signs on the subjects hands do not require a second check and require only the successful skill check (DC 10) other more obscure jobs require the check (DC 15) to gain any knowledge about the subjects line of work.
If you want to try for a specific observation the DC is 15 to 25 or higher.
Retry: Yes but each time a character makes an observation, each time this is done however the chance of the characters attentions being noticed by the subject.