Non-monk unarmed fighter

[Unkabear]

A fighter or swashbuckler with perhaps a level of rogue or two going into invisible blade. True he would be using daggers instead of unarmed strike, but they are easy to conceal and keep with the feel of the original concept I think (aside from the pugilist barehanded fighter bit). Plus int to ac. I have not seen a swordsage going into invisible blade yet...int + wis + dex to ac could be interesting if not MAD and the maneuvers could add quite a bit of spice to the character.

 

[griff_goodbeard]

IF you don't mind multiclassing...

Human Warblade 1/ incarnate 2/ WB +1/Swordsage 1/ I +1/ SS +1/ I +1 (WB 2/I 4/SS 3)
Feats: W Finesse, Shape Soulmeld (mauling gauntlets), Imp Essentia Capacity, Bonus Essentia, Shadow Blade

Focus on Dex, Wis and Con

BAB 6 and fairly good saves

+12 damage on your unarmed strikes and Imp Unarmed Strike from mauling gauntlets + Dex, + and str.

Nice little array of maneuvers too.

 

[blargney the second]

Have a look at a high Dex swordsage/fighter with Improved Unarmed Strike, Superior Unarmed Strike, Shadow Blade, and Weapon Finesse. You won't be disappointed. (The levels of fighter are just there to get you the feats a little earlier. Two levels does it pretty quickly.)
-blarg

 

[Thurbane]

Best two option are a Battledancer, or a Fighter with feat chains in unarmed attacks.

 

[Gloombunny]

You'll still have the Wis bonus to AC, but you'll probably want to get some maneuvers that bump AC or allow you to negate attacks. Unfortunately, Wall of Blades from Iron Heart isn't a Swordsage discipline.

You could get it anyway with a Martial Study feat or a one-level dip in Warblade, but since it specifies that you have to be holding a melee weapon it wouldn't help anyway.

The unarmed swordsage variant is the way to go, I think. Or if the GM doesn't allow it, then a regular swordsage with Superior Unarmed Strike, and at least you can wear light armor that way. For defense, there's a Shadow Hand stance that gives you concealment as long as you move 10+ feet every round. A 20% miss chance would go a long way to making up for low AC. Setting Sun has counters that help evade attacks, and Stone Dragon strikes give you temporary DR.

Also, unarmed strike is a preferred weapon for Shadow Hand, which means you can use the Shadow Blade feat to add Dexterity to damage. If you take that and Weapon Finesse, you can neglect Strength in favor of a very high Dex for more AC.