I've been looking for a carbon fiber seat post to give a little extra cushion on those long rides/races. I know its not much but every little bit helps, right?

I can't find the right size to fit my bike anywhere. I have a Cervelo Eyre Tri (the last year they made it before stopping, then going to the One). It takes a 28.9 diam post. I can't so much as find a brand that makes that size. I tried emailing Cervelo about 2 weeks ago, but have gotten no reply. Any help would be greatly appreciated.