I realize you're trying to validate a Fighter here, but dipping will improved things a lot.
Passive Way Monk 6 gets free Combat Expertise & Improved Trip, but also +4 to Trip if his opponent is Flat-Footed if he takes Skill Focus(bluff). You also pick up Unarmed Boosts and FoB (more attacks!). Going Monk 7 gives you uber stealth as well.
From there, you could dip Barbarian, both for the fun Lion-Totem abuse but also and more importantly, Whirling Frenzy which gives an extra attack, wording is one extra attack per round yet leaves out the requirements to be Full-Attacking, so hey use it on an AoO. The additional Str boost will help Trip checks as well, and you can buy extra Rage uses as needed.
Then consider Factotum 3, it's Int to Strength checks. Per Trip: If your attack succeeds, make a Strength check opposed by the defender’s Dexterity or Strength check (whichever ability score has the higher modifier). So theres yet more bonuses, because you never know when you need to trip a giant spider. Also this gives Int to Initiative making you have an even faster reaction time, and you can pick up skills like Iaijitsu Focus, it's a skill based on drawing your sword fast.
Finally, go Fighter. Well, not normal Fighter of course, use the Drow sub for +2 to Initiative Dex to Damage and against Flat-Footed foes, which via Dark Moon Disciple form Monk, they pretty much always are. You want to pick up Double Hit & Robilar's Gambit with your Fighter Dip. For your normal 12th you want the flat-out extra attack granter, Snap Kick.
Warblade at this point is nice. It rounds out some missing traits and lets you pick up Dancing Mongoose, bu hey w/e. Just take Weapon Focus & Planar Touchstone(oxyrhynchus). Honestly, picking up an extra two Feats would allows for GTWF and Knock-Down, so I'd look into Psychic Fighter or something.
You should be somewhere at: TWF(F), Dodge(F), Karmic Strike (1st), Improved Unarmed Strike(B), Combat Expertise(B), Improved Trip(B), Skill Focus[Bluff](3rd), Combat Reflexes(6th), ITWF(9th), Double Hit(B), Robilar's Gambit(B), Snap Kick(12th), Weapon Focus[unarmed strike](15th), Planar Touchstone[oxyrhynchus](18th) or better.
You've got super stealth, and by that I mean you have Full-Concealment virtually all the time for near spell immunity and 50% chance to by missed by an attack (kind of ruins karmantic strike) which sets up the Dex to Damage & +4 to Trip. While Raging, you can take a -9 penalty to attack with an AoO you attack five items at your highest BAB. Once for your main hand, then off hand, then snap kick, then oxyrhynchus, then of course whirling frenzy. This sequence it's self is triggered up to twice, once for Robilar's Gambit and a possible second time for Karmic Strike. Pretty much, if you have the Dex and AC for it you attack everyone eight times for each attack they fail to hit you with and Whirling tosses in an extra attack in there somewhere. And I'm not saying Trip an already Prone Opponent (which btw the FAQ says no) to hit this number.
On your Full-Attack, you FoB, Monk 7 + Belt means you get Greater Furry. That's +2~+3 for TWF, +2 Fob, +1 Snap Kick, +1 Oxyrhynchus, maybe +1 Haste, and +1 Dancing Mongoose usable every other round if you want speed over double damage per attack, which is an option to pick up if you tweak the build just a hair. So you don't have to wait for someone to attack you either. If you did pick up Knock-Down, you can also Trip as part of a normal attack, so you never have to pick between Tripping or dealing damage.
Amazing what can be done when Fighter 20 is dropped to Fighter 2. It's like D&D hates them...
