Commercial Airplanes' 2011 deliveries guidance is expected to be between 485 and 500 airplanes and is sold out. It includes the first 787 and 747-8 deliveries (combined 25 to 40 units), which are expected to begin in the third quarter of 2011 and mid-2011, respectively.
Boeing has about 16 747-8 built (including the first 747-8I) and assuming they build one per month will imply that Boeing may have about 28 747-8 built by the end of 2011. Currently Boeing has about 22 production 787s built. Assuming 2/month build rate for 6 months (12) and then 3/month build rate for the last 6 months (18) will give Boeing 52 787s built through the end of the year.
I think that the 747-8s production is in a better state compared to the 787 thus of the 787s and 747s to be delivered it would be more of the later. There is simply too much re-work to be done on the 787s that are already built and waiting on the Everett flight line. Boeing may opt to deliver the later build aircraft which are expected to be more fully completed and requiring little re-work to be done. If Boeing is to deliver 40 787s and 747s I think it would be about 25 747s and 15 787s. It will all depend on how fast they can re-work the 787s (and some of the 747s) as well as how smooth the production ramp up goes on the 787 line.
Boeing's 2010 earnings press release
Scott Hamilton just put out a piece on 747 and 787 deliveries, he feels that 18 747s are realistic but the number of 787s will be fewer than 22:
Scott Hamilton: Boeing projects 20-40 747-8, 787 deliveries this year
Here are a couple of articles from Aspire Aviation and FleetbuzzEditorial.com following on the heels of Boeing's earnings announcement:
Aspire: Boeing posts mixed 2010 4th quarter, full year results
Saj Ahmad: Boeig 737 will be replaced not re-engined