The magazine I read today (forgot the name, British though) had a very honost in depth feature about both the A-380 and the Sonic Cruiser.
The magazine article who's author seemed to have a very reliable contact within Boeing mentioned the aircraft we call Sonic Cruiser may be called the 808, the 808 would represent a new generation of technology and aircraft similar to the 707. Also 808 is a lucky number amongst many Asian cultures.
This would also leave a 787 and 797 series to continue along the lines of more conventional aircraft. They mentioned a Super economical aircraft to replace both the 737 and 757 lines, this is probably what people are calling the Yellow Stone project. This is about 10 years from entering service.
Another interesting item mentioned in the article I read today is that many analyst and engineers believe the Sonic Cruiser is actually not a new totally new design, they feel many of the features of the SC were designed for a US Military Stealth aircraft that may or may not exist in some form.
Eastern Air lines flt # 701, EWR-MCO Boeing 757