According to the review at dpreview.com, they couldn't get 6.5fps either, and they only got up around 6 when the shutter speed was very fast. IIRC they needed 1/4000 sec to get above 6 fps. Not particularly useful when shooting, say, indoor basketball.
(Disclosure: I have a 40d on order, but haven't shot one yet. I won't be using it for sports photography. That's why I have 1-D2 bodies.)