I read yesterday the first article about delays in 787 deliveries in 2013 due to the grounding of the fleet. With the investigation of the batteries issue taking already a month, it was evident that these delays were going to happen.
I have not yet read anything in the specialized or business press about cancellations. However, taking into account that when the 787 program started announcing 3-month delays from Q3 2007, cancellations started to pile, I guess that this time it will not be very different.
I checked the information of orders and cancellations from Boeing website.
Since 2004, Boeing has received a total of 1,112 787 orders. Out of these, 222 orders were later on cancelled; mostly between 2008 and 2012. Now there are still 890 firm orders (with about 50 of those aircraft already delivered). As a summary, find the graphic below: