Also, there is a Great Scimitar from the Sandstorm book. While not a Falchion, the damage is 1d8, 18-20 x2 crit, so it's similar. It's like the Bastard Sword, martial as 2H, exotic as 1H, so they'd still be taking EWP plus TWF and Oversized TWF in order to have a reasonable chance to hit something.