Who makes the lightest stock carbon fiber frame these days? At various times, I've reade specs from the web sites of Trek, Scott and Giant saying they make the lightest "stock" carbon fiber frame. They can't all be right. Is there an independent lab that weighted these frames (and others) of the same size for comparison? Just curious. I was thinking about building a bike strictly for climbing.

The Weight Weenies website has a wealth of frame & component weights information . Here's the link for the frame weights table:
http://weightweenies.starbike.com/listings/components.php?type=roadframes

Happy hunting!!!
DIG

The Scott CR-1 Limited is the lightest stock carbon frame of the moment.

I think the Cervelo Bayonne is 880g as well. But, if you're building a climbing bike you should spend as much or more time worrying about your wheels. For "reasonable" money look at the Reynolds Cirro KOM's ... around $2K US, 1050g.

For sure, the stock Ksyrium SSC SL's on the Scott bike are NOT the answer for a pure climbing bike.