New 777 upgrades/variants + 787-10 upcoming?

Looks like Boeing is planning to <squeeze> the 3510 with 777-9X, concept for a stretched 77W, fm above(i.e. Bigger, more performance but lower fuel efficiency) and 7810, concept for a stretched 789, fm below(i.e. Smaller, less performance but higher fuel efficiency):
http://www.flightglobal.com/articles/2011/06/21/358550/paris-boeing-mulls-777-9x.html

That's a pretty cunning+relatively low cost(Easy to justify incremental upgrade investment for the already hugely profitable 777program and a simple 789-stretch is easy+cheap to develop) product strategy designed to exploit that huge gap in Airbus' widebody portfolio between 388 and 3510 while undermining 3510(i.e. Customers can choose 1 of 2 Boeings that's either more capable or more efficient than the 3510)......mounting pressure on 3510 sales.

And Boeing is already studying EIS dates:
http://www.flightglobal.com/articles/2011/09/13/361971/boeing-studies-service-entry-timing-for-planned-new.html

Given that Airbus has delayed the EIS of 3510 to End2017, I think it's now possible for Boeing to respond with similar EIS for 777-9X/7810 shortly after 3510's.

Resurrecting this topic with some recent news re progress of these 2 derivative concepts:
http://www.aspireaviation.com/2012/01/11/boeing-eyes-787-improvements-along-with-production-ramp-up/#.Twx-hU_OaYE.twitter

My prediction of the 300seater widebody mkt in 2020:
1) The extra-longhaul(Upto 14-16hrs sectors) mkt segment owned by 772ER today since about 2000 will be largely taken over by 359.
2) The medium-to-longhaul(Upto 8-10hrs sectors) mkt segment owned by 333 today since about 2000 will begin to be taken over by 7810X.

So basically, Airbus and Boeing will swap their relative dominance in each others stronghold segment.