Mi Note Plus could be Xiaomi's second Snapdragon 810-powered smartphone
It looks like the Mi Note Plus features an octa-core Snapdragon 810 processor, 4 GB of RAM, a 13 MP rear camera, and a 1440 x 2560 pixels screen - just like the Mi Note Pro. Moreover, the handset runs Android 5.0 Lollipop, but there's no way of telling if it resembles the Mi Note Pro design-wise.
As you may know, both the Mi Note and Mi Note Pro are China-only devices. Earlier today, Xiaomi announced a Mi Note Natural Bamboo Edition, but this, too, will be available only in China. So maybe Xiaomi intends to release the Mi Note Plus in other markets.
Since the Mi Note Pro costs around $530, the Mi Note Plus may have a similar price (of course, that's assuming that this handset will be launched somewhere at some point).
sources: Geekbench, GizmoChina, MyDrives