A level of
this monster class could get you a shadow hand maneuver and stance without losing BAB but you wouldn't be able to be a Tibbit without taking two feats which puts you back where you started. If you weren't attached to being a Tibbit, though, it could work nicely as it also grants some natural attacks.
Alternatively, the
Dragonheart Adept gets you the maneuver but not the stance (it also gets a crap ton of other stuff that may or may not work with your concept.)
That's all I can find so far but I am certain there has to be a homebrew initiating class out there somewhere that has both full BAB and Shadow Hand as an available discipline. I'm going to keep looking and post here if I turn up anything.
EDIT:
Found one. Not sure if it would work for you, but it will qualify you for Shadow Blade without losing BAB.
EDIT 2:
Here's another one. This one's a Hexblade fix which might be more appropriate for your concept than a Barbarian/Ranger/Scout (or it might not.)
