One of my players is potentially starting as a P.I, so I went ahead and created a talent tree specifically for the P.I, using Marshal, Thief and a couple of other tree's to get talents from.
The idea behind the P.I is that it is a fairly flexible career with a good range of skills directed at information gathering, bribery, computers and light combat. However, as you'll notice, no specific area contains duplicate talents (exception to shortcut, point blank) so the P.I is ideally suited with a complement specialization. If someone wants to a hardened P.I, they could go down the road of P.I > Enforcer. If someone wants stealth as a primary focus, P.I > Thief, etc.
Here's the tree for anyone wishing to use.
(Link Removed)
Edited by Xyd