I saw a news just now concerning SAC seeming to have formed a new development team: "JJ"team, first J is for "军品项目部" , or Military Project Department; second J is for “结构部”, or Structure Department (I believe the "structure" refers to the airframe design of planes).
link:
Pic 1 is the mark of the team, and according to the original article published by the official wechat account of SAC, the shape symbolizes the cross-section of an aircraft (looks kinda like an airliner with its round fusalage and winglet, but I dont believe that's what the final product will be... explination further down) According to the article, this plans for the project started in June 2018 and the project itself was initiated in September 2018.
Pic 2 is a shot taken at a award-giving ceremony on 10th December 2019 feturing some of the development teams. The plack held by the group to the left has "Development Team on Composite Material Overall Structure (or Molothic Structure, depends on how one interprets the word)"; Middle group is "Proof-of-Concept Team on Advanced Materials"; and to the right is "Development Team on Monolithic (One-Piece) Structure Metal Air Intake"
Pic 3 is taken probably at a group meeting, and the red bannar hung on the wall is "...进战机S弯进气道攻关团队", or roughly "...dvanced combat aircraft (note that the bannar says '战机' and not ‘战斗机’; the latter specifically refers to fighter jets, but the first one I believe *may* refer to other types of combat aircraft) S-shaped air intake tackling team"
So based on what we know, SAC is working on a new project of some kind with large-scale use of composite material and a S-shaped air intake. 99% probability its some kind of stealth aircraft, but unforturnately at the moment we just don't know what it is. My personal speculation is that this project is somehow linked with the new factory building that was under construction in SAC since last year ( I'll post some satellite pics below with its construction progress at various times) and is either finished or almost finished as of now.
Things that I don't quite get: In pic 2 they specifically said "metal air-intake" which is kind of wired IMO because I remembered that most of the stealth aircrafts (F-35 for example) had composite air-intakes?
NEW SAC FACILITY:
Pic 4: satellite pic on 20th January 2018 (which happens to be my birthday lol), I believe the two red-circled buildings are the assembly plants, because they are the only one building that are linked to the runway with roads that are wide enough for a flanker (blue circled road, the size issue is better shown in later pics where there are flankers for comparison) Construction of new facility (which will appear to the right of the two existing plants) have not started. (I initially thought the facility to the left of the existing assembly plant is also for assembly, but then realized that the green-circled part is actually a field of grass)
Pic 5: satellite pic on 4th October 2018 (around 3 months after plans for the project is made and 1 month after the project officially began), the new facility is under destruction (red circle). Note that there are several planes on the runway next to the existing facility, which includes one flanker, and the relative size of the planes to the roads that lead to the existing facilities.
Pic 6: Satellite pic on 22th August 2019, which is the newest pic available to me right now. The new facility is almost finished (still a patch of earth between the old and new facilities, I believe this would be paved shortly afterward the pic was taken) Note that the new facility is more than 2 times as big as the existing one. (Possibly a Pulse Line? I believe there were news a few years back concerning new pulse line under construction in Chengdu for the J-20 too)
IMO whatever SAC got their hands on with this project, its BIG, like REALLY BIG, certainly bigger than a production plant that can produce around 50 flankers a year can handle without seriously expanding their assembly line.
(BTW sorry for posting pics in thumbnails, the first 3 pics aren't very cooperative but I think they will open if u click on the image)