Well heres my thought... even though your two cheap to spare a penny...
There would be 6 piece sets, 2 terran 2 zerg and 2 toss so each player could be whatever he/she (heheh he she) wants.
Terran:
Pawn: Marine
Knight: Vulture
Bishop: Goliath
Castle: Siege Tank
Queen: Sarah Kerrigan
King: Either
A: A marine with the visor up showing the face of Jim raynor
B: A ghost with the face of alexie stukov.
I prefer B cuz stukov kicks ass
Zerg:
Pawn: Zergling
Knight: Hydralisk
Bishop: Defiler
Castle: Ultralisk
Queen: Infested Kerrigan
King: Either
A: A cerebrate
B: The Overmind
I know neither A nor B move, but the king tends not to move much til the near end of the game, and work with me here! >.<
Protoss:
Pawn: Zealot
Knight: Dragoon
Bishop: High Templar
Castle: Either
A: Reaver
B: Archon
Queen: Razsagal ( the dt form )
King: Either
A: A high templar with a dif face to show its tassadar
B: A high templar Psi assaulting to show its tassadar
C: An Archon
D: A Reaver
I suppose there could be a set with air units, but i dont feel like making that up. I also suppose pawns coulsd be the worker units, but i prefer the basic attackers.
Now I'm Gonna Go Get :wasted