This is a build I was thinking of that uses an interesting combination of Dragonborn and Kobolds.
Dragonborn keeps any abilities that are based off of your size, such as Slight Build or Powerful Build.
So we grab a pair of Kobolds and enlarge them to Medium, and then make them Dragonborn. This a. makes the size change permanent and b. can give them some nifty stuff. Nifty stuff is less useful than the fact that, since they basically count as small when it suits them, kobolds should still qualify for feats or classes that require size Small or Smaller. The reason for this assumption is that Goliaths count as large because of Powerful Build, which uses similar language to Slight Build.
So what does this mean? It means we can do the following:
Dragonborn Kobold Fighter 2/Marshal 1/Warblade X
Feats (Not in Order): Swarmfighting, Confound the Big Folk, Shield Wall, Phalynx Fighter, Underfoot Combat.
The point of this is that you can stick 2 of these guys in a square, and they gain nice benefits for each ally that has the same feats that is adjacent/threatening the same enemy, so they get them as long as theri budy is in the same space as them.
Funnily enough, these guys are massive threats to people of Large size or larger, because they can effectively stand in his square and laugh at him.
If I made any mistakes, please tell me.