It is very different from what I read from the furom. the rumour I heard is CAC is developing next generation twin engine interceptor with SAC's help, especially in structure. SAC is response for next generation twin engine multi-role aircraft which is focus on cost efficiency. SAC will use Flanker as base to develop a ultimate "Flanker" like F-15SE.
Regarding J-10 in PLAAF, I didn't see PLAAF treat J-10 production as first priority. Last year(2009), a picture from SAC show J-11B is in massive production phase. Dozens J-11B is parking in SAC and waiting for engine. While J-10 import another 100 engine from Russian. The only engine suitable for J-11B is Ws-10 in China. From this two new, I think it is clear show PLAAF treat J-11B as the first priority and allocate most production capacity of ws-10a to SAC. beside that PLAN's goal is J-15.(J-15 use ws-10a as well)
I believe upgrade verion J-10 is in development, but I think twin-engine J-10 is more like a joke, add another engine will cause a major structure change. PLAAF will better off with upgrade J-11.