Before I go on, this post highlighting some prevalent anti-Central/Northern Asian portrayals in Chinese media is excellent and, also, applicable to various non-Han portrayals in general as well. I also just saw this quick interesting thread on examples of anti-Central/Northern Asian portrayals and this thread on hair braids being deeply charged, deeply political markers of non-Han identity.
Firstly, on ( Peerless by Meng Xi Shi )
Secondly, on ( Thousand Autumns by Meng Xi Shi )
Thirdly, ( The Fourteenth Year of Chenghua by Meng Xi Shi )