Here's a pic of a carbon stab I made a few weeks ago (the side rod, that is). I bought the carbon fiber a while ago but just finally got around to turning the ends and the weights. The od of the shaft is .64" but I can't quite remember what the id is off hand. All I know is that's its relatively thick and is plenty stiff; maybe even a little bit of an overkill considering the length, which is 12".
Compared to my B-stinger premiere plus (which is my main bar in the pics) in the same length, it's smaller in diameter, but quite a bit heavier. Over all I'm happy with the end results.
The weights I turned are a 4oz, 2oz, and 3 1oz weights. The lathe I was using had quite a bit of chatter, but with a little sanding they turned out all right. Not quite as smooth as B-stinger weights but still very usable.
Let me know what you think