Here's a suggested build for you that does what you want it to do while retaining full BAB

Ranger11/Fighter4/Dread Commando 5//Rogue1/Swordsage1/Rogue4/Assassin5/Swordsage1/Bloodclaw Master2/Rogue6

For a total of: Ranger11/Fighter4/Dread Commando 5//Rogue11/Assassin5/Swordsage2/Bloodclaw Master2
You get the following maneuvers and stances:

1st level of Swordsage (at character level 2): Emerald Razor Strike (target is flat-footed for the attack), 3 Tiger Claw Maneuvers, Island of Blades (Stance, lets you flank much easier)
2nd level of Swordsage (at character level 11): Pouncing Strike and Assassin's Stance

In short: 9d6 sneak attack, 3d6 sudden strike, POUNCE (full attack on charge, that means you get your full round of all attacks with both weapons, including all precision-based damage on every attack), with the option to either do 11d6 sneak attack OR only do 9d6 sneak attack, but you can flank with allies that are adjacent to the opponent you are adjacent to without needing proper flanking.

This will MASSIVELY increase your ability to apply sneak attack damage, and will allow you to One-Hit-Kill most critters you run up against. You still get Rogue11 for Improved Evasion (although I'd get Skill Mastery so you can Take 10 on UMD to activate Wands of Golembane/Gravebane which are in Wand Sheathes in your two weapons so you can apply all precision-based damage to almost anything you encounter).