This is just in the air right now, lol. I saw it on their list as ‘in preparation’ but it was there since 2014. But of course it makes sense that it would be a long preparation, considering how they’re planning to have the same team as DGSD and DOMD do it. (Check here and scroll all the way down to list of adaptations to see that someone already filled out the placeholder for it.)
Possible cast so far? I managed to find a clip of Zhang Meng being interviewed and she hoped to work with Han Dong. My thoughts? Um, how about no? I love them together in DOMD, but I don’t think they’re suitable to portray Guo Jing and Huang Rong. The production team should find actual suitable candidates instead. I liked some of their past decisions, but if they end up casting Han Dong and Zhang Meng, they have to really convince me. Han Dong, though I love him, had already pushed it as Xiao Bao (age-wise). I also have a hard time imaging Han Dong portraying a dumb character. Okay, Guo Jing’s just too honest at times, but next to Huang Rong, he seems soooo dumb, lol. Han Dong doesn’t have the dumb face, lol. He just looks too smart and cunning. (Xu Zhu only appeared a bit versus Guo Jing role so I sort of went along with it when watching DGSD, lol. Not to mention, Han Dong can’t just wrinkle his face all the time for the Guo Jing role.) As for Zhang Meng, I might change my mind later if they do a good job with image and see how her acting goes this time around.
If Huace must use someone within their company though, I think Jia Qing would fit the role Huang Rong perfectly. I’m not kidding. I have seen a lot of Jia Qing’s performances in the past few years. She really could pull off various roles and she could be quite cunning and/or mischievous as needed. Not to mention playful. She, of course, could also be quite serious as well. It would be awesome also if the plot is right. (I do understand if they do go ahead with this adaptation, it would be like the umpteenth time for this novel so I will try to understand their stretch, considering how I didn’t mind–as much–their exaggerations in the past 2 Jin Yong adaptations that I ended up watching.) Don’t ask me who’s a suitable candidate for Guo Jing, because it is indeed very hard. Good luck!
EDIT (9/15/15): I just thought of something, Maybe Zhang Han could be Guo Jing. He looked quite good with her in The Four (even if I wasn’t in favor of the pairing in there, mostly due to plot). He could pull it off.