Do you want "tanky" as in just able to take hits, or "tanky" as in drawing the monsters to you and keeping them off your party as well as taking hits?
The former is straightforward of course. The latter will require some feats like
Stand Still perhaps and the
Thicket of Blades stance most likely, which won't be a problem of course.
Or you could go with another kind of control build. How much cheese is the DM willing to go with, specifically with the Aptitude weapon enhancement? One of the cheesiest tricks is making use of it with Bloodstorm Blade and
Boomerang Daze. More info on a specific build for that can be found
http://brilliantgameologists.com/boards/index.php?topic=12015.0]here.
Even if your DM won't allow a chain to count as a boomerang, being able to throw your weapon around and use that to bull rush and trip stuff is awesome.
Do you expect damage itself to actually matter a lot? Sure, it's possible to get thousands of damage in a round, but that can be pretty difficult to set up for and so it's generally better to control the enemy in such a way that you can reliably splat it without going splat yourself.
How far are custom items allowed to go? It's possible to get a continuously active item of True Strike for 4,000g by going strictly by the rules, which likely isn't intended at all.