Bladesinger PrC build.

[true_shinken]

I know that. It's stupid.

I disagree. Legacy decisions are what kept 3rd edition from becoming 4th edition, after all.

Perform (sing) and Perform (dance) are cross-class for both Fighters and Wizards. The PrC should have been overhauled.

And that's why it only requires a few ranks. What's the problem if a few cross-class skills? Dancing/singing is only fluff for the Bladesinger any way - their gist is attacking with one hand and casting with the other.
The problem with Bladesinger is the execution. 3.0 Bladesinger was fine, Races of Faerun Bladesinger was fine (though the requirements were a bit steep) but CW Bladesinger sucks with that half casting.
The class I find most fitting for the concept is, of course, the Duskblade. That's why I wrote a Bladesinger sub level for it.