FWIW:
I'm 5'10" 240# & have a Giant OCR Limited (carbon frame) w/ Xero XSR-3 20/24 spoke wheels.
http://archive.giant-bicycles.com/us...06&model=11445
http://www.xerowheel.com/prod_detail...&id2=19&pid=20
After 2500+ miles I have had
no issues w/ the frame or wheels.
Having said that, remember that carbon needs to be 'babied' more than Steel, Al, or TI. Minor trauma that would only be a small dent or just scrape the paint on other frames could be catastophic for carbon.
Have you ever heard of anyone crushing an aluminum downtube with a repair stand clamp???