I found this little idea on the gleemax forums, a.k.a. the wizard boards. It sounded like a nice idea to, and even though it will not end up in 4e, I might house-rule it.
Also made me think, perhaps there could be one defence for each ability?
Made this new feat up over the past hour or so... Tell me what you think :)
I'm not totally happy with the name of the feat and options....
Co-Operative Fighting[Tactical]
Prerequisites: Combat Expertise; Improved Disarm; Improved Trip; Base Attack Bonus +6
Benefit: You gain access to three...