On ebay of course...I just ordered one. Seller has >500 100% positive feedback. I have nothing to do with him other than purchasing this item from him. Wanted to share the incredible deal as he has only 4 left:
Easton EC90 Zero Setback 27.2 x 300 post
EDIT: I also discovered that Speedgoat has these for $165...I thought it was a typo but one of their staff told me it was right. Everywhere else these go for $219.
Their link is HERE